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.’”

Exodus 34:9

34:9 and said, “If now I have found favor in your sight, O Lord, let my Lord go among us, for we are a stiff-necked people; pardon our iniquity and our sin, and take us for your inheritance.”