Chp. 19 verse 4 - chp. 20 verse 11: G-d tells Moshe what to tell the people, and they answer "all that G-d has spoken we will do." Moshe tells them to purify themselves, separate from their wives for three days, and to not touch the mountain, neither man nor beast. On the third day G-d comes down to the mt. and calls out to Moshe who ascends the mt. G-d once again tells him to warn the people not to touch the mt. and he goes down. Chp. 20 begins the introduction to the ten commandments.