And Moses charged the people the same day. In order that both the promises and threats might have more efficacy in affecting the minds of all, God enjoined not only that they should be proclaimed in a solemn rite, but also that they should be approved by the people in a loud voice, and sealed, as it were, by their consent. It is elsewhere recorded that this was faithfully performed by Joshua. (Joshua 8:33.) Let it suffice to say at present that they were all summoned, and conducted before God to subscribe to them, so that henceforth all subterfuge might be put an end to. The tribes of Israel were divided into two parties, that they might stand opposite to each other, and that the blessings might sound forth from one side, and the curses from the other, [1] like antistrophoi. I confess I do not know why the descendants of Simeon, Levi, Judah, Issachar, Joseph, and Benjamin, were chosen by God to proclaim the blessings, rather than the others; [2] for there is no force in the opinion of the Hebrew writers that those who descended from free mothers were placed in the post of highest dignity: since the tribe of the first-born, Reuben, was united with some who sprang from the bond-maids; unless, perhaps, we may say that the descendants of Reuben were degraded into the second class as a mark of ignominy; but, since both the blessings and curses were offered in the name of the whole people, it is not a point of much importance. For, if this division was made to bear witness to their common consent, it was equivalent to their all alike confessing that the transgressors of the Law were accursed, and those who kept it blessed; and consequently I am not very curious to know why, in their common office, God preferred some to the others. Moses will elsewhere relate that the tribes, which are here separated, were then united together. It would perhaps be a probable conjecture that God, who well knew what would hereafter be the inheritance of every tribe, placed them severally in that station which would correspond to their future allotment. In order that the sanction might have more solemnity, God chose that the Levites should dictate the words as if He Himself spoke from heaven; for, since they were appointed to be the expounders of the Law, as it behooved them faithfully to repeat what God had dictated out of His own mouth, so they were heard with greater attention and reverence.

Footnotes

1 - "Comme correspondantes." -- Fr. "It was also customary on some occasions to dance round the altars whilst they sung the sacred hymns, which consisted of three stanzas or parts; the first of which, called strophe, was sung in turning from east to west; the other, named antistrophe, in returning from west to east: then they stood before the altar and sung the epode, which was the last part of the song." -- Potter's Antiq. of Greece, Book II. chap. 4.

2 - "The six nobler tribes answered amen to the blessings; the six more ignoble to the curses, viz., four who descended from the children of the hand-maids, i.e., Gad, Asher, Dan, and Naphtali, to whom Reuben is added, because he had defiled his father's bed incestuously; and Zebulun, because he was the youngest son of Leah. So Raban and Theod., q. 34." -- Corn. a Lapide, in loco.

Compare Joshua 8:32-35. The solemnity was apparently designed only for the single occasion on which it actually took place.

And Moses charged the people the same,.... That he gave the above orders to set up stones, and plaster them, and write the law on them, and build an altar in the same place, and offer sacrifices when come into the land of Canaan:
saying; as follows.

The six tribes appointed for blessing, were all children of the free women, for to such the promise belongs, Galatians 4:31. Levi is here among the rest. Ministers should apply to themselves the blessing and curse they preach to others, and by faith set their own Amen to it. And they must not only allure people to their duty with the promises of a blessing, but awe them with the threatenings of a curse, by declaring that a curse would be upon those who do such things. To each of the curses the people were to say, Amen. It professed their faith, that these, and the like curses, were real declarations of the wrath of God against the ungodliness and unrighteousness of men, not one jot of which shall fall to the ground. It was acknowledging the equity of these curses. Those who do such things deserve to fall, and lie under the curse. Lest those who were guilty of other sins, not here mentioned, should think themselves safe from the curse, the last reaches all. Not only those who do the evil which the law forbids, but those also who omit the good which the law requires. Without the atoning blood of Christ, sinners can neither have communion with a holy God, nor do any thing acceptable to him; his righteous law condemns every one who, at any time, or in any thing, transgresses it. Under its awful curse we remain as transgressors, until the redemption of Christ is applied to our hearts. Wherever the grace of God brings salvation, it teaches the believer to deny ungodliness and wordly lusts, to live soberly, righteously, and godly in this present world, consenting to, and delighting in the words of God's law, after the inward man. In this holy walk, true peace and solid joy are to be found.

THE TRIBES DIVIDED ON GERIZIM AND EBAL. (Deuteronomy 27:11-13)
These shall stand upon mount Gerizim to bless the people . . . these shall stand upon mount Ebal to curse--Those long, rocky ridges lay in the province of Samaria, and the peaks referred to were near Shechem (Nablous), rising in steep precipices to the height of about eight hundred feet and separated by a green, well-watered valley of about five hundred yards wide. The people of Israel were here divided into two parts. On mount Gerizim (now Jebel-et-Tur) were stationed the descendants of Rachel and Leah, the two principal wives of Jacob, and to them was assigned the most pleasant and honorable office of pronouncing the benedictions; while on the twin hill of Ebal (now Imad-el-Deen) were placed the posterity of the two secondary wives, Zilpah and Bilhah, with those of Reuben, who had lost the primogeniture, and Zebulun, Leah's youngest son; to them was committed the necessary but painful duty of pronouncing the maledictions (see on Judges 9:7). The ceremony might have taken place on the lower spurs of the mountains, where they approach more closely to each other; and the course observed was as follows: Amid the silent expectations of the solemn assembly, the priests standing round the ark in the valley below, said aloud, looking to Gerizim, "Blessed is the man that maketh not any graven image," when the people ranged on that hill responded in full simultaneous shouts of "Amen"; then turning round to Ebal, they cried, "Cursed is the man that maketh any graven image"; to which those that covered the ridge answered, "Amen." The same course at every pause was followed with all the blessings and curses (see on Joshua 8:33-34). These curses attendant on disobedience to the divine will, which had been revealed as a law from heaven, be it observed, are given in the form of a declaration, not a wish, as the words should be rendered, "Cursed is he," and not, "Cursed be he."

With the solemn erection of the stones with the law written upon them, Israel was to transfer to the land the blessing and curse of the law, as was already commanded in Deuteronomy 11:29; that is to say, according to the more minute explanation of the command which is given here, the people themselves were solemnly to give expression to the blessing and the curse: to the former upon Mount Gerizim, and to the latter upon Ebal. On the situation of these mountains, see at Deuteronomy 11:29. To this end six tribes were to station themselves upon the top or side of Gerizim, and six upon the top or side of Ebal. The blessing was to be uttered by the tribes of Simeon, Levi, Judah, Issachar, Joseph, and Benjamin, who sprang from the two wives of Jacob; and the curse by Reuben, with the two sons of Leah's maid Zilpah, and by Zebulun, with Daniel and Naphtali, the sons of Rachel's maid Bilhah. It was natural that the utterance of the blessing should be assigned to the tribes which sprang from Jacob's proper wives, since the sons of the wives occupied a higher position than the sons of the maids - just as the blessing had pre-eminence over the curse. But in order to secure the division into two sixes, it was necessary that two of the eight sons of the wives should be associated with those who pronounced the curses. The choice fell upon Reuben, because he had forfeited his right of primogeniture by his incest (Genesis 49:4), and upon Zebulun, as the youngest son of Leah. "They shall stand there upon the curse:" i.e., to pronounce the curse.