Exodus 19:5

19:5 And now, if you will diligently listen to me and keep my covenant, then you will be my special possession out of all the nations, for all the earth is mine,

Exodus 19:14-15

19:14 Then Moses went down from the mountain to the people and sanctified the people, and they washed their clothes. 19:15 He said to the people, “Be ready for the third day. Do not go near your wives.”