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 Deu 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 Deu 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 Dan 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 (Gen 49:4), and upon Zebulun, as the youngest son of Leah. “They shall stand there upon the curse:” i.e., to pronounce the curse.