There were eleven curses given in Parshat Ki Savo. Yet there were twelve tribes. It seems there should have been twelve curses (by the way, the last, twelfth posuk in the section of curses is not counted for it is a general statement, not a curse). Why was this?
- Heard 8/27/99 from R. Vogel
The answer is that Moshe instructed the Jews to give the curses knowing that later on he would give the blessings to the tribes. The tribe of Shimon (because of the sin of Zimri) would not be given a blessing. Therefore, in order for there to be a balance, Moshe only specified eleven curses.
The purpose of the curses was to curse things that were normally hidden and innocuous...(for instance, the forbidden relationship between a mother in law and son in law, no one would condemn a son in law for hanging around with his mother in law). There are some sins, like hitting a person, that everyone sees and immediately recognizes as wrong, and do not go unnoticed. But there are some sins that do go unnoticed generally, and it was important that as soon as the Jews crossed into Israel that they would make a statement that they stood against sins that are generally unnoticed.
Another purpose of declaring curses was to make a point regarding bullies. Sometimes bullies are able to push others into not condemning them for sinning. These eleven curses were a curse that cursed all such bullies for all times.