1.

Behold, I will send my messenger, and he shall prepare the way before me: and the Lord, whom ye seek, shall suddenly come to this temple, even the messenger of the covenant, whom ye delight in: behold, he shall come, saith the LORD of hosts.

Behold, I will send, &c. = Behold Me sending, &c. Quoted in Matthew 11:10 . Mark 1:2 .Luke 1:76 ; Luke 7:27 . Not to that then present generation, but to the "generation" of our Lord's day. See note on Matthew 11:18 . This is the answer to the question "Where? "in Malachi 2:17 .
My messenger . John the Baptist (Matthew 3:3 ; Matthew 3:11 , Matthew 3:10 . Mark 1:2 , Mark 1:3 .Luke 1:76 ; Luke 3:4 ; Luke 7:26 , Luke 7:27 , John 1:23 ). Compare Matthew 22:2 , Matthew 22:3 .Isaiah 40:3-5 .
prepare . By removing obstacles from the way. Compare Isaiah 40:3 ; Isaiah 62:10 .
the Lord. Hebrew. ha-Adon . App-4 . This refers to Messiah. Ref to Pentateuch (Exodus 23:20 Exodus 33:14 , Exodus 33:16 ). App-92 .
suddenly = unexpectedly.
behold Figure of speech Asterismos ( App-6 ), for emphasis.
said = hath said.
the Lord of hosts. See note on Malachi 1:4 .

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:

who may abide. ? Compare Joel 2:11 . Figure.
abide = endure
soap = lye; as in Job 9:30 , i.e. water mixed with the ashes of certain plants containing alkali. Compare Mark 9:3 .

3.

And he shall sit as a refiner and purifer 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.

He shall purify. Judgment begins at the house of God. See 1 Peter 4:17 .
offer = bring near.
offering = a gift offering. Hebrew. minchah . Not the same word as in Malachi 3:8 .

4.

Then shall the offering of Judah and Jerusalem be pleasant unto the LORD, as in the days of old, and as in former years.

Then. When Jehovah shall have sent His messenger (Messiah), and He is accepted.

5.

And I will come near to you to judgment; and I will be a swift witness against the sorcerers, and against the adulterers, and against false swearers, and against those that oppress the hireling in his wages, the widow, and the fatherless, and that turn aside the stranger from his right, and fear not me, saith the LORD of hosts.

I will be, &c. Compare Micah 1:2 .
the sorcerers . Reference to Pentateuch (Exodus 22:18 . Deuteronomy 18:10 ).
adulterers. Reference to Pentateuch (Exodus 20:14 .Leviticus 20:10; Leviticus 20:10 ).
oppress, &c. Reference to Pentateuch (Exodus 22:21 .Deuteronomy 24:14; Deuteronomy 24:14 ) App-92 .
fear = revere.

6.

For I am the LORD, I change not; therefore ye sons of Jacob are not consumed.

For I change not . Reference to Pent (Numbers 23:19 ) App-92 . Not in Himself, nor in His purpose, to change His dealings on the conditions stated.

7.

Even from the days of your fathers 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?

ordinances = statutes. Hebrew, hok . Referring to particular ritual observances. Not the same word as in Malachi 3:14 .

8.

Will a man rob God? Yet ye have robbed me. But ye say, Wherein have we robbed thee? In tithes and offerings.

man . Hebrew 'adam. App-14 .
rob = defraud. A rare word. Occurs only here, in Malachi 3:8 , Malachi 3:9 ; and Proverbs 22:23 .
God . Hebrew. Elohim . App-4 .
have robbed = are defrauding.
tithes. Reference to Pentateuch (Leviticus 27:30-33 .Numbers 18:21-32 .Deuteronomy 12:17 , &c.; Mal 14:22-29 ). App-92 .
offerings = heave offerings. Literally, in the tithe and the heave offering. Hebrew. trumah. App-43 . Not the same word as in verses: Malachi 3:3 , Malachi 3:4 , Malachi 3:10 , Malachi 1:11 , Malachi 1:13 ; Malachi 2:12 , Malachi 2:13 .

9.

Ye are cursed with a curse: for ye have robbed me, even this whole nation.

are cursed with a curse. The primitive text read, "ye have cursed Me with a curse". The Sopherlm say ( App-33 ) that they altered the letter, (Mem = M) into; (Nun = N), thus making it passive instead of active, and detaching it from the rest of the sentence. This was done to avoid a supposed irreverence.
this whole nation = the nation, the whole of it.

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.

all = the whole; implying that a part had been withheld.
meat prey: i.e. animals for sacrifice. Not put by Figure of speech Metonymy (of Adjunct), App-6 , for food; but put by Figure of speech Synecdoche (of Species), App-6 , for sacrificial animals.
open you the windows, &c. Reference to Pentateuch (Genesis 7:11 ; Genesis 8:2 ). App-92 .
pour you out = empty you oat.

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.

the devourer = the eater: i.e. the locust. Compare Joel 1:4 .Amos 4:9 .
for your sakes = for you (the Dative of Reference),

12.

And all nations shall call you blessed: for ye shall be a delightsome land, saith the LORD of hosts.

a delightsome land. Compare Isaiah 62:4 .Daniel 8:9 .

13.

Your words have been stout against me, saith the LORD. Yet ye say, What have we spoken so much against thee?

stout = hard, or bold.

14.

Ye have said, It is vain to serve God: and what profit is it that we have kept his ordinance, and that we have walked mournfully before the LORD of hosts?

ordiance = charge. Hebrew. mizvah . Not the same word as in Malachi 3:7 . Referring to general religious duties.
walked mournfully before = gone off mournfully from the presence of Jehovah of hosts.

15.

And now we call the proud happy; yea, they that work wickedness are set up; yea, they that tempt God are even delivered.

And now. Compare Malachi 1:9 , Malachi 2:1 .
are set up = prosper, or are successful. Lit are built up. Put by Figure of speech Metonymy (of Subject), App-6 , for being prospered. Compare Job 22:23 .Jeremiah 12:16 .
yea = yea, [they, proud ones]. Marking a climax.
tempt = have tempted. Same as "prove" in Malachi 3:10 ; but here in a bad sense, as though to challenge or to put to the proof.

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.

Then: i.e. when Malachi had spoken thus unto them, at a time of such apostasy, show us what is possible and practicable in these like days and "perilous times" which are closing this present Dispensation.
feared = revered.
spake. As in Malachi 3:13 .
one to another. Each one with his friend.
and. Note the Figure of speech Polysyndeton , App-6 .
hearkened, and heard. As He heard the groaning of Israel (Exodus 2:23 , Exodus 2:24 ); Moses, without words (Exodus 14:15 ); and Nehemiah (Nehemiah 2:4 ); Hannah, without words (1 Samuel 1:13 ); Jeremiah, his breathing (Lamentations 3:55 , Lamentations 3:56 ); Jonah, when dying (Jonah 2:2 ); the disciples, their thoughts (Luke 24:15 , Luke 24:38 ).
and a book of remembrance. Some codices, with Syriac, read "a record was written in a book of remembrance". remembrance. Reference to Pentateuch (Exodus 28:29 . Numbers 10:10 , the same word). App-92 .
thought. Precious comfort for those now who cannot speak. We can walk with God (like Enoch, in the darkest days), and think of Him with these God-reverers now, in these similar days.

17.

And they shall be mine, saith the LORD of hosts, in that day when I make up my jewels; and I will spare them, as a man spareth his own son that serveth him.

I make up, &c = I am preparing.
My jewels = A peculiar treasure.

18.

Then shall ye return, and discern between the righteous and the wicked, between him that serveth God and him that serveth him not.