This is the conclusion of the sermon. He ends, as he should, with a command to repent. What Jacob does do is highlight the reversal of expectations. He tells the Nephites not to revile the Lamanites, if the Lamanites are better than they are.
In verse 10 he asks that they remember their children. It is interesting that there is no declaration that any should divorce any wives. The command is to remember their children, and what is being taught to them. It is speculation, because this is all Jacob gives us, but it appears that Jacob is willing to allow those with multiple wives to continue in the responsibilities they have made to those families. The injunction would be to stop the practice, and teach the children that it should not occur.