Exodus 34:8-10

And Moses made haste, and bowed his head toward the earth, and worshipped. And he said, If now I have found favor in thy sight, O Lord, let the Lord, I pray thee, go in the midst of us; for it is a stiffnecked people; and pardon our iniquity and our sin, and take us for thine inheritance. And he said, Behold, I make a covenant: before all thy people I will do marvels, such as have not been wrought in all the earth, nor in any nation; and all the people among which thou art shall see the work of Jehovah; for it is a terrible thing that I do with thee.