Yahweh Confirms That He Is Renewing The Covenant (Exodus 34:10).
God replies by confirming the covenant and guaranteeing the receipt of the inheritance. He does not need to repeat the ten words. He has already confirmed that they will be written on the new tablets that Moses has brought (Exodus 34:1). Instead He guarantees the fulfilment of the covenant in practical terms by promising the manifestation of His power and that He will do wonders on their behalf.
The fact that these marvels are to be ‘created' stresses that they will be of Yahweh. He alone is the Creator. The verb for ‘create' is never used unless Yahweh is involved. He will create marvels such as the world has never known, and no nation has ever experienced. In view of what He did in Egypt these are strong words. What He will do with His people will be awesome and terrible, even more terrible than He did in Egypt (compare Deuteronomy 10:21; Psalms 106:22). That He did do marvels we know, using extraordinary natural events to assist His people (e.g. Joshua 3:13; Joshua 6:20; Joshua 10:11-14; Judges 5:19-22). What He would have done had they been faithful and obedient and entered the land when He said is beyond our imagination.
‘And he said, “Behold, I make a covenant. Before all your people I will do marvels such as have not been created in all the earth, nor in any nation. And all the people among whom you are will see the work of Yahweh, for it will be a terrible thing that I will do with you.” '
This is the promise that He is renewing the covenant, and that He is going to do wonders on their behalf which will manifest how terrible He is. Kings at the time constantly sought to establish to their people how terrible they were to rebels and to their enemies. In the same way the nations, with all their debased religion, among whom they are, will see what Yahweh will do, and will be filled with awe.