Read Deuteronomy 10:21 Using Other Translations
He is thy praise, and he is thy God, that hath done for thee these great and terrible things, which thine eyes have seen.
He is your praise. He is your God, who has done for you these great and terrifying things that your eyes have seen.
He alone is your God, the only one who is worthy of your praise, the one who has done these mighty miracles that you have seen with your own eyes.