Exodus 34:8-10

8And Moses made haste, and bowed his head to the earth and worshipped,

9and said, If indeed I have found grace in thine eyes, Lord, let the Lord, I pray thee, go in our midst; for it is a stiff-necked people; and pardon our iniquity and our sin, and take us for an inheritance!

10And he said, Behold, I make a covenant: before all thy people I will do marvels that have not been done in all the earth, nor in any nation; and all the people in the midst of which thou [art] shall see the work of Jehovah; for a terrible thing it shall be that I will do with thee.