Exodus 12:13

12:13 The blood will be a sign for you on the houses where you are, so that when I see the blood I will pass over you, and this plague will not fall on you to destroy you when I attack the land of Egypt.

Exodus 33:5

33:5 For the Lord had said to Moses, “Tell the Israelites, ‘You are a stiff-necked people. If I went up among you for a moment, I might destroy you. Now take off your ornaments, that I may know what I should do to you.’”