Exodus 34:10

And the Lord said, Behold, I lay down [afresh the terms of the mutual agreement between Israel and Me] a covenant. Before all your people I will do marvels (wonders, miracles) such as have not been wrought or created in all the earth or in any nation; and all the people among whom you are shall see the work of the Lord; for it is a terrible thing [fearful and full of awe] that I will do with you.