Reflections on Malachi 2:1-5

1 “And now, O priests, this commandment is for you.
2 If you will not hear,
And if you will not take it to heart,
To give glory to My name,”
Says the LORD of hosts,

“ I will send a curse upon you,
And I will curse your blessings.
Yes, I have cursed them already,
Because you do not take it to heart.
3 “ Behold, I will rebuke your descendants
And spread refuse on your faces,
The refuse of your solemn feasts;
And one will take you away with it.
4 Then you shall know that I have sent this commandment to you,
That My covenant with Levi may continue,”
Says the LORD of hosts.
5 “ My covenant was with him, one of life and peace,
And I gave them to him that he might fear Me;
So he feared Me
And was reverent before My name.
(NKJV)

God sends out His commandment to the priests, to give glory to His name. The priests who had been given the honour and privilege of guiding God's chosen people but who so far have fallen very short of God's standards. The Lord says unflinchingly that if the priests continue with their flippant and deceitful ways, He will curse their blessings. And He warns them that He has already cursed them because they have not taken His commandment to heart. This would mean the taking away of all and everything that God has provided for them in abundance.

Their misconduct will not only affect them, but also their descendants who will be chastised and rebuked by God. And that God now regards their offerings as dung. He goes on to remind the priests that He has sent this commandment to them that He may re-establish the covenant with Levi. This was a covenant of both life and peace.

Just as God had made a covenant with Israel (a kingdom of priests), He had also set apart the house of Aaron to be a family of priest. Aaron and his descendants - under the tribe of Levi, were chosen for service in the house of the Lord. This is recounted in tbe book of Numbers, which describes how Israel under the leadership of Moses was in the desert region of Sinai, preparing to enter the Promised Land.

Numbers 1:48-53 (NKJV)

48 for the LORD had spoken to Moses, saying: 49 “Only the tribe of Levi you shall not number, nor take a census of them among the children of Israel; 50 but you shall appoint the Levites over the tabernacle of the Testimony, over all its furnishings, and over all things that belong to it; they shall carry the tabernacle and all its furnishings; they shall attend to it and camp around the tabernacle. 51 And when the tabernacle is to go forward, the Levites shall take it down; and when the tabernacle is to be set up, the Levites shall set it up. The outsider who comes near shall be put to death. 52 The children of Israel shall pitch their tents, everyone by his own camp, everyone by his own standard, according to their armies; 53 but the Levites shall camp around the tabernacle of the Testimony, that there may be no wrath on the congregation of the children of Israel; and the Levites shall keep charge of the tabernacle of the Testimony.”

Numbers 3:5-13 (NKJV)

5 And the LORD spoke to Moses, saying: 6 “Bring the tribe of Levi near, and present them before Aaron the priest, that they may serve him. 7 And they shall attend to his needs and the needs of the whole congregation before the tabernacle of meeting, to do the work of the tabernacle. 8 Also they shall attend to all the furnishings of the tabernacle of meeting, and to the needs of the children of Israel, to do the work of the tabernacle. 9 And you shall give the Levites to Aaron and his sons; they are given entirely to him^[a] from among the children of Israel. 10 So you shall appoint Aaron and his sons, and they shall attend to their priesthood; but the outsider who comes near shall be put to death.”
11 Then the LORD spoke to Moses, saying: 12 “Now behold, I Myself have taken the Levites from among the children of Israel instead of every firstborn who opens the womb among the children of Israel. Therefore the Levites shall be Mine, 13 because all the firstborn are Mine. On the day that I struck all the firstborn in the land of Egypt, I sanctified to Myself all the firstborn in Israel, both man and beast. They shall be Mine: I am the LORD.”

Numbers 25:10-13

10 Then the LORD spoke to Moses, saying: 11 “Phinehas the son of Eleazar, the son of Aaron the priest, has turned back My wrath from the children of Israel, because he was zealous with My zeal among them, so that I did not consume the children of Israel in My zeal. 12 Therefore say, ‘Behold, I give to him My covenant of peace; 13 and it shall be to him and his descendants after him a covenant of an everlasting priesthood, because he was zealous for his God, and made atonement for the children of Israel.’”

References:
1. Matthew Henry's Commentary of the Bible
http://www.ccel.org/h/henry/?show=worksBy

2. John Calvin's Commentary of the Bible
http://www.ccel.org/c/calvin/?show=worksBy

3. The Spirit-Filled Bible (NKJV)

4. Life Application Bible (NIV)