Moses continues to remind the people of what happened in the past.

## hardened his mind and made his heart obstinate ##

Both of these phrases mean the same thing and are combined to emphasize that the God caused the king to be very stubborn. (See: [[rc://en/ta/man/translate/figs-parallelism]])

## to deliver up Sihon and his land before you ##

AT: "to give Sihon and his land over to you"