Malachi was writing to God’s people, who for the most part were going thier ways, picking and choosing which of the commandments they would follow.
Chapter 3 begins by telling the people, God would send a messenger, John the Baptist, to prepare the way so people could receive the fulfilling of the promise, the arrival of the Messiah.
1 Behold, I will send my messenger, and he shall prepare the way before me: and the Lord,
John came preaching strong of repentance and being cleansed. His words showing the need of a refiner’s fire and fuller’s soap for a cleansing deeper than sorrowful words, but real turning from their old ways to obedience to God.
2 But who may abide the day of his coming? and who shall stand when he appeareth? for he is like a refiner’s fire, and like fullers’ soap:
3 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.
The God of the fathers, of Abraham, Isaac, Jacob , the God of Moses, Joshua, Samuel and David, the unchanging LORD was saying again to His people, return/
6 For I am the LORD, I change not;
Return unto me, and I will return unto you, saith the LORD of hosts
Give me, bring to me all that I ask, not more of your what you think I want, or less because of your selfishness. Bring and I will pour out a blessing. Bring, and I will protect your future prosperity.
10 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.
11 And I will rebuke the devourer for your sakes, and he shall not destroy the fruits of your ground; neither shall your vine cast her fruit before the time in the field, saith the LORD of hosts.
Those people of God who believed his words acted daily in specific ways:
16 Then they that feared the LORD spake often one to another: and the LORD hearkened, and heard it, and a book of remembrance was written before him for them that feared the LORD, and that thought upon his name.
They that feared the Lord
1. They feared the Lord. They had that reverence for Jehovah that caused them to depart from evil, and to keep his ordinances.
2. They spake often one to another. They kept up the communion of saints. By mutual exhortation they strengthened each other’s hands in the Lord.
3. They thought on his name. His name was sacred to them; it was a fruitful source of profound and edifying meditation. The name of God is God himself in the plenitude of his power, omniscience, justice, goodness, mercy, and truth. What a source for thinking and contemplation!
See how God treats such persons: The Lord hearkened to their conversation, heard the meditations of their hearts; and so approved of the whole that a book of remembrance was written before the Lord – all their names were carefully registered in heaven. Clarke’s Commentary
17 And they shall be mine, saith the LORD of hosts, . . .