I prayed therefore... and said. — The words that follow are very similar to those which are recorded in Exodus 32:11-13. Moses appears to be alluding to his first intercession here, before he descended from Sinai for the first time.
Related Commentaries of Deuteronomy 9:26
Deuteronomy 9:26
26 I prayed therefore unto the LORD, and said, O Lord GOD, destroy not thy people and thine inheritance, which thou hast redeemed through thy greatness, which thou hast brought forth out of Egypt with a mighty hand.