Charles Ellicott Commentary Exodus 34:10

"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." — Exodus 34:10 (ASV)

I make a covenant —that is, “I lay down anew the terms of the covenant that I am willing to make with Israel. I will go with them, and drive out the nations before them (Exodus 34:11), and work miracles on their behalf (Exodus 34:10), and enlarge their borders (Exodus 34:24), and prevent their enemies from desiring their land at the festival seasons (Exodus 34:24); they, on their part, must ‘observe that which I command them this day.’”

The “command” given included the moral law, as laid down in the Ten Commandments (Exodus 34:28), and a summary of the chief points contained in the “Book of the Covenant,” which must be regarded as a re-publication and re-authorisation of that book.

Marvels, such as have not been done in all the earth —for example, the drying up of Jordan (Joshua 3:16–17), the falling down of the walls of Jericho (Joshua 6:20), the destruction of the army of the five kings by hailstones (Joshua 10:11), and the like.

A terrible thing. —Compare Deuteronomy 10:21; Psalms 106:22; Psalms 145:6. God is “terrible” to the enemies of His people.