Deuteronomy 2:14

2:14 Now the length of time it took for us to go from Kadesh Barnea to the crossing of Wadi Zered was thirty-eight years, time for all the military men of that generation to die, just as the Lord had vowed to them.

Deuteronomy 7:8

7:8 Rather it is because of his love for you and his faithfulness to the promise he solemnly vowed to your ancestors that the Lord brought you out with great power, redeeming you from the place of slavery, from the power of Pharaoh king of Egypt.