1 Chronicles 24

This chapter relates the distribution David made of the priests into twenty four classes or courses, and which were observed by lot, and each course had an head or principal man over it, #1Ch 24:1-19 and of a like distribution of the Levites into the same number of courses, to attend the priests in theirs, #1Ch 24:20-31. (Gill)

The division of the priests and Levites into classes.-Vv. 1-19. The twentyfour classes of priests. After the statement as to the fathers'-houses of the Levites (ch. 23), we have next the arrangements of the priests for the performance of the service in the sanctuary; the priestly families descended from Aaron's sons Eleazar and Ithamar being divided into twenty-four classes, the order of whose service was settled by lot. (KD)

The particular account of these establishments is of little use to us now; but, when Ezra published it, it was of great use to direct their church affairs after their return from captivity into the old channel again. The title of this record we have #1Ch 24:1—These are the divisions of the sons of Aaron, not by which they divided one from another, or were at variance one with another (it is a pity there should ever be any such divisions among the sons of Israel, but especially among the sons of Aaron), but the distribution of them in order to the dividing of their work among themselves; it was a division which God made, and was made for him. (MH)

V. 2, Nadab and Abihu. See my notes in Leviticus 10.

MH's outline:

First, God was an is a God of order, not of confusion. He is particularly concerned about the things of His worship. Numbers without order gives an occasion of tumult. Everyone has, knows and keeps his place in the work assigned to him by the Lord (by lot). As everyone fulfills his responsibility, God's work will prosper.

Second, each person's place was determined by lot, or the hand of the Lord. Thus, there could be no quarrels nor contentions, nor charges of partiality, nor wrong. God determined who was to do what.

Proverbs 16:33 The lot is cast into the lap; but the whole disposing thereof is of the LORD.
Proverbs 18:18 The lot causeth contentions to cease, and parteth between the mighty.

The New Testament is abundant with instructions to be content with our "lot" in life:

Luke 3:14 And the soldiers likewise demanded of him, saying, And what shall we do? And he said unto them, Do violence to no man, neither accuse any falsely; and be content with your wages.
Philippians 4:11 Not that I speak in respect of want: for I have learned, in whatsoever state I am, therewith to be content.
1 Timothy 6:8 And having food and raiment let us be therewith content.
Hebrews 13:5 Let your conversation be without covetousness; and be content with such things as ye have: for he hath said, I will never leave thee, nor forsake thee.

Third, the lot was cast publically, in the presence of the king, princes and priests. There, hence, was no room for fraud nor of suspicion. It is wise that our actions, especially the things that effect others, be done in public, and recorded in public record, v. 6.

Acts 26:26 For the king knoweth of these things, before whom also I speak freely: for I am persuaded that none of these things are hidden from him; for this thing was not done in a corner.

Fourth, evidently, the course to which the families were chosen her by lot and under David's direction, remained in effect until the temple was destroyed by Rome.

Note here the care David took to establish everything he possibly could before his death. Not only did he lay up unbelievable wealth for the use in the temple, but he established the order by which God was to be served in the temple.

Vv. 20ff.

MH points out from v. 31:

And, that the whole disposal of the affair might be of the Lord, the principal fathers cast lots over against their younger brethren; that is, those that were of the elder house came upon the level with those of the younger families, and took their place, not by seniority, but as God by the lot directed. Note, In Christ no difference is made between bond and free, elder and younger. The younger brethren, if they be faithful and sincere, shall be no less acceptable to Christ than the principal fathers.