I am the law and the light. Look unto me, and endure to the end, and ye shall live; for unto him that endureth to the end will I give eternal life…
This is the law and the prophets, for they truly testified of me. 
The Old Testament closes with a final warning and plea to the house of Israel to come unto Christ and to be perfected in Him. Zechariah and Malachi, a prophet whose eye was “fixed on the restoration of the priesthood [and] the glories to be revealed in the last days,”  describe the sequence of events that will lead up to the Savior’s coming in glory. They also lay out what is required of those who will come unto Him and partake of His Atonement.
They Weighed for My Price Thirty Pieces of Silver
Zechariah prophesied around 530 B.C. after many Israelites had returned to Jerusalem to rebuild the temple. Looking forward, Zechariah is not optimistic about the times. He clearly sees that the renewed Jewish priesthood will eventually backslide and exchange their callings as “shepherds of Israel” for worldly rewards. “There is a voice of the howling of the shepherds; for their glory is spoiled… Feed the flock of the slaughter; whose possessors slay them, and hold themselves not guilty: and they that sell them say, Blessed be the Lord; for I am rich: and their own shepherds pity them not.” 
He means of course that the priesthood would become corrupt, valuing position and wealth more than their callings to serve the people. This prophecy was fulfilled by the time of Jesus, who instead of being recognized and hailed by the priests ofIsrael, was betrayed by them. They saw him as a threat to their status; and as they met in council, they plotted to eliminate him: “What do we? for this man doeth many miracles. If we let him thus alone, all men will believe on him: and the Romans shall come and take away both our place and nation.” 
They Shall Look Upon Me Whom They Have Pierced
For this betrayal, as Zechariah points out, the Lord would withdraw His covenant from the house of Israel and leave them to languish in apostasy: “I will not feed you; that that dieth, let it die; and that that is to be cut off, let it be cut off… and I took my staff… and cut it asunder, that I might break my covenant which I had made with all the people.” 
Zechariah thus prophesies that the Lord would no longer honor His covenant and would turn Israel over to masters who would prey on them and rule them without mercy: “For, lo, I will raise up a shepherd in the land, which shall not visit those that be cut off, neither shall seek the young one, nor heal that that is broken, nor feed that that standeth still: but he shall eat the flesh of the fat.” 
Because Israel would reject the true Shepherd, God would give them over to the control of “anti-shepherds” — that is, the self-aggrandizing, pitiless rulers of this world. The rejection of Jesus the true Shepherd caused the world to fall into darkness: “Woe to the idol shepherd that leaveth the flock! The sword shall be upon his arm, and upon his right eye: his arm shall be clean dried up, and his right eye shall be utterly darkened.”  Thus the earth was to be at the mercy of armies of oppressive tyrants who themselves would be destroyed for their wickedness. History, from the ruthless Emperor Nero to Hitler and Stalin, bears out this prophecy.
Eventually, Zechariah indicates, this order of things will culminate in a great war, a “siege against Judah and Jerusalem… all the people of the earth [shall] be gathered against it.”
In that day shall the Lord defend the inhabitants of Jerusalem… I will seek to destroy all the nations that come against Jerusalem. And I will pour upon the house of David, and upon the inhabitants of Jerusalem, the spirit of grace and of supplications: and they shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son, and shall be in bitterness for him, as one that is in bitterness for his firstborn. <
And one shall say unto him, What are these wounds in thine hands? Then he shall answer, Those with which I was wounded in the house of my friends. 
Then shall the Lord go forth, and fight against those nations… And his feet shall stand in that day upon the mount of Olives, which is before Jerusalem on the east, and the mount of Olives shall cleave in the midst thereof toward the east and toward the west. 
Section 45 of the Doctrine and Covenants gives a clearer account of the appearance of the Savior at that crisis point:
Then shall the Lord set his foot upon this mount [the Mount of Olives], and it shall cleave in twain… And then shall the Jews look upon me and say: What are these wounds in thine hands and in thy feet? Then shall they know that I am the Lord; for I will say unto them: These wounds are the wounds with which I was wounded in the house of my friends. I am he who was lifted up. I am Jesus that was crucified. I am the Son of God. And then shall they weep because of their iniquities; then shall they lament because they persecuted their king. 
Once the great war is over, the Savior will bring the bright millennial day, “one day which shall be known to the Lord, not day, nor night: but it shall come to pass, that at evening time it shall be light. And it shall be in that day that living waters shall go out from Jerusalem… And the Lord shall be king over all the earth.” 
The living waters are symbolic of the purifying water of baptism, which shall be applied to those who desire it. The “fountain [that] shall come forth of the house of the Lord” represents the cleansing power of the Savior’s blood: “For I will cleanse their blood that I have not cleansed: for the Lord dwelleth in Zion.” 
Return Unto Me, and I Will Return Unto You
To prepare for that “great and dreadful day,” the Lord pleads with us through the prophet Malachi to “return unto me.” The prophet chastises the people for certain selected transgressions and lays out what we must do to come unto Christ and be perfected in Him.
Coming about a century after Zechariah, Malachi lived to see the renewed corruption of Israel that Zechariah had prophesied. Considered by the Jews the last of the prophets, Malachi was probably a priest who deeply understood the dark path his nation was on. “The name Malachi means ‘my angel,’ suggesting that the prophet was a priest, since the priests were held to be angels on earth. Malachi condemned the priests of his time because they offered polluted bread on the altar, and they polluted the Lord (Mal. 1.7). They gave false teaching and in so doing endangered the covenant, when it was the duty of a priest, as an angel of the Lord of Hosts, to guard knowledge.” 
Malachi was unusually candid in warning the covenant people of his time of the danger they were in; but his message is just as important for us as it was for them — because it was aimed at us.
The prophecies of Malachi have a peculiar relevance to Latter-day Saints. They were crucial enough that the Savior Himself recited the third and fourth chapters to the people of Nephi during his ministry to them. “And it came to pass that he commanded them that they should write the words which the Father had given unto Malachi… after they were written he expounded them.”  Malachi’s words must be of critical importance to us because Jesus said of them: “The Father commanded that I should give [these scriptures] unto you; for it was wisdom in him that they should be given unto future generations.”  Of course, we are those future generations.
Jesus then “expounds,” or explains, Malachi to the people of Nephi — and to us. These scriptures, He says, focus on “the time that he should come in his glory… the great and last day, when all people, and all kindreds, and all nations and tongues shall stand before God, to be judged of their works… according to the mercy, and the justice, and the holiness which is in Christ.” 
To emphasize the importance of Malachi’s words, Moroni quoted them to Joseph Smith repeatedly the night of September 21, 1823: “He first quoted part of the third chapter of Malachi; and he quoted also the fourth or last chapter of the same prophecy,” intimating that these passages were not yet fulfilled but soon would be. 
What is so crucial about Malachi’s message that the Savior would insist that we focus our attention on it?
Because, as Joseph Smith wrote, Malachi “had his eye fixed on the restoration of the priesthood [and] the glories to be revealed in the last days”  when the Lord will return.
Before that return, Malachi prophesies, “I will send my messenger, and he shall prepare the way before me: and the Lord, whom ye seek, shall suddenly come to his temple, even the messenger of the covenant.” 
Elder Jeffrey R. Holland explains that “Christ, who is the great ‘messenger of the covenant,’ did come to the first temple in this dispensation, in Kirtland, Ohio, on April 3, 1836. He has, of course, come to other temples and will yet do so… as part of the culmination of his majestic second coming.”
The whole purpose of the Restoration of the Gospel is to prepare the way for Christ’s return. The keys of the priesthood had to be restored at the Kirtland Temple. With these keys, the latter-day priesthood has what is necessary to prepare the world for His coming. The writings of Malachi lay out for us what we must do to prepare adequately for Him to come unto us — and for us to come unto Him.
“Return unto me and I will return unto you”  : this is the substance of Malachi’s message.
Offer Unto the Lord a Sacrifice in Righteousness
To come unto the Lord we must obey the law of sacrifice by making a “pure offering.” This meant the same thing to the people of Malachi’s time that it means to us, although the sacrificial tokens are different. In Malachi’s day, the tokens were the best of the flock and of the fruits of the field. In our day, the tokens are the bread and the water of the sacrament.
To those people of former days, the Lord said, ‘Ye offer polluted bread upon mine altar… Ye have profaned it…Ye said also, Behold, what a weariness is it! And ye have snuffed at it… and ye brought that which was torn, and the lame, and the sick; thus ye brought an offering: should I accept this of your hand?”
Malachi’s people were guilty of offering the worst they had on the Lord’s altar, but these defective sacrifices were merely indicators of the state of their hearts. The prophets had taught them that “the sacrifices of God are a broken spirit: a broken and a contrite heart, O God, thou wilt not despise.”  So the Lord considered their offering “contemptible” because it was not only contrary to His order but also unaccompanied by the true sacrifice of repentance and contrition for sin. They obviously had no zeal for the ordinances (“what a weariness is it!”) and had no respect for the Atonement of the Lord.
We of the latter days are confronted with the same choice. The Lord has said to us, “Thou shalt offer a sacrifice unto the Lord thy God in righteousness, even that of a broken heart and a contrite spirit.”  As Malachi promised, the “sons of Levi” (the Aaronic priesthood) once again have the restored authority to “offer unto the Lord an offering in righteousness”  as they administer the sacrament to us. The question arises: What do we bring to the altar? Do we take the sacrament thoughtlessly? Do we consider the making of a covenant with God each week a “weariness”? Or do we genuinely bring to the Lord’s table the sacrifice of “a broken heart and a contrite spirit”?
If we take the sacrament in token of our love for the Lord and our repentance for our sins, we become purified: “Then shall the offering of Judah and Jerusalem be pleasant unto the Lord.”
Keep the Covenant of Chastity
To come unto the Lord we must keep the law of chastity. Malachi was straightforward with the members of the priesthood of his day on this subject. “And now, O ye priests,” he says, “this commandment is for you.” 
Apparently, these former-day priests were unfaithful to their wives. “Judah hath dealt treacherously, and an abomination is committed in Israel and in Jerusalem: for Judah hath profaned the holiness of the Lord which he loved, and hath married the daughter of a strange god.” 
Some interpret this passage of Malachi as a figurative attack on the priests for engaging in idol worship. There is an additional possibility — along with worshiping idols, the priests were also abandoning their own wives to commit adultery with foreign, idolatrous women.
The Lord hath been witness between thee and the wife of thy youth, against whom thou hast dealt treacherously: yet is she thy companion, and the wife of thy covenant. And did not he make one? …and wherefore one? That he might seek a godly seed. Therefore take heed to your spirit, and let none deal treacherously against the wife of his youth. For the Lord, the God of Israel, saith that he hateth putting away [divorce]. 
Likewise, prophets have indicated that the greatest threat to the priesthood of the latter days is failure to live the law of chastity and the concomitant failure of marriage. President Ezra Taft Benson said, “The plaguing sin of this generation is sexual immorality. This, the Prophet Joseph said, would be the source of more temptations, more buffetings, and more difficulties for the elders of Israel than any other.”
Without chastity, there is no “godly seed” or rejoicing in one’s posterity. Without chastity, there is no eternal union of husband and wife — “did not he make one?” Without chastity, there is no blessing of exaltation in the celestial kingdom of God.
President Benson also said, “On the other hand, when we obey the law of chastity and keep ourselves morally clean, we will experience the blessings of increased love and peace, greater trust and respect for our marital partners, deeper commitment to each other, and, therefore, a deep and significant sense of joy and happiness” 
Bring Ye All the Tithes Into the Storehouse
To come unto the Lord we must live by a covenant of consecration. Malachi rebuked the people of his day: “Ye are gone away from mine ordinances, and have not kept them. Return unto me, and I will return unto you, saith the Lord of Hosts. But ye said, Wherein shall we return?”
Then Malachi asks the pointed question:
Will a man rob God? Yet ye have robbed me. But ye say, Wherein have we robbed thee? In tithes and offerings. Ye are cursed with a curse: for ye have robbed me, even this whole nation.
Bring ye all the tithes into the storehouse, that there may be meat in mine house, and prove me now herewith, saith the Lord of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough to receive it. 
We of the latter days confront the same challenge, and for many the payment of tithing is a real obstacle to coming unto Christ. Furthermore, the expression “all the tithes” ought to be translated “a full tithe.” But the requirement is clear and the promise is sure. In fact, the original Hebrew word rendered as “windows” probably is better translated as “floodgates.” In some non-English translations, the promise here becomes “cataracts” or “torrents” of blessings.
And we need them, particularly in a time when we want for our families the further promise that the Lord “will rebuke the devourer for your sakes, and he shall not destroy the fruits of your ground.”  As President James E. Faust teaches, “In our time we are surfeited with a pestilence of violence, evil, and wickedness in so many forms. Those who keep their covenants and pay their tithes and offerings will have some extra defense against these virulent modern-day forms of evil. But this protection will not come with a sacrifice which costs us nothing.” 
Those who love the Lord will pay a full tithe to demonstrate their consecration and devotion to building His kingdom. A tithe is the merest token of our willingness to give something back to Him who atoned for us “through the shedding of his own blood.”  After all, as President Faust says, “The ultimate offering was that offered by the Savior Himself in giving His very life. It causes each of us to wonder, How many drops of blood were shed for me?” 
Turn Your Hearts to Your Fathers
Coming unto the Lord ourselves means bringing our families with us. To come unto the Lord, we must turn our hearts to our fathers and do our best to perform the saving work for them in the temples.
Through Malachi, the Lord promised:
“I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord; and he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.” 
Of this puzzling promise, the Prophet Joseph Smith taught:
[Malachi] had his eye fixed on the restoration of the priesthood, the glories to be revealed in the last days, and in an especial manner this most glorious of all subjects belonging to the everlasting gospel, namely the baptism for the dead. . . .
It is sufficient to know, in this case, that the earth will be smitten with a curse unless there is a welding link of some kind or other between the fathers and the children, upon some subject or other — and behold what is that subject? It is the baptism for the dead. 
By helping the Lord with His saving work for the dead, we come unto Him and become like Him. We are doing the work that is his peculiarly His: becoming a savior. President Gordon B. Hinckley teaches: “Just as our Redeemer gave His life as a vicarious sacrifice for all men, and in so doing became our Savior, even so we, in a small measure, when we engage in proxy work in the temple, become as saviors to those on the other side who have no means of advancing unless something is done in their behalf by those on earth “ 
Behold, The Great Day of the Lord Is at Hand
Only those who offer themselves in these ways will be able to abide the “great and dreadful day of the Lord.” Ours is the great blessing and privilege of making pure offerings, of maintaining ourselves tender and chaste before the Lord, of consecrating unto Him, and helping Him in His saving work. In reflecting on the words of Malachi, the Prophet Joseph Smith gave us this sacred challenge:
Behold, the great day of the Lord is at hand; and who can abide the day of his coming, and who can stand when he appeareth? For he is like a refiner’s fire, and like fuller’s soap: and he shall sit as a refiner and purifier of silver, and he shall purify the sons of Levi, and purge them as gold and silver, that they may offer unto the Lord an offering in righteousness. Let us, therefore, as a church and a people, and as Latter-day Saints, offer unto the Lord an offering in righteousness. 
 3 Ne. 15:9-10.
 D&C 128:17.
 Zech. 11:3-5.
 John 11:47-48.
 Zech. 11:12; Matt. 26:14-16.
 Zech. 11:9-10.
 Zech. 11:16.
 Zech. 11:17.
 Zech. 12:9-10.
 Zech. 13:6.
 Zech. 14:3-4.
 D&C 45:48, 51-53.
 Zech. 14:7-9.
 Joel 3:18, 21.
 Margaret Barker, The Great High Priest: The Temple Roots of Christian Liturgy, London: T&T Clark, 2003, 152
 3 Ne. 24:1.
 3 Ne. 26:2.
 3 Ne. 26:3-5.
 JS-History 1:36.
 D&C 128:17.
 Mal. 3:1.
 Jeffrey R. Holland, Christ and The New Covenant, Deseret Book, 1997, 294.
 Mal. 3:7.
 Mal. 1:7, 12-13.
 Psalm 51:17.
 D&C 59:8.
 Mal. 3:3.
 Mal. 3:4.
 Mal. 2:1.
 Mal. 2:11.
 Mal. 2:14-16.
 “What Prophets and Apostles Teach about Chastity and Fidelity,” Ensign, Oct. 1998, 38.
 Mal. 3:7-10.
 Mal. 3:11.
 James E. Faust, “Opening the Windows of Heaven,” Ensign, Nov. 1998, 54.
 D&C 76:69.
 Faust, 54.
 Mal. 4:5-6.
 Discourses of President Gordon B. Hinckley Volume 2, Deseret Book: 2005, 265.
 D&C 128:17-18, 24.