The address of Moses here resumes where it was left off at the end of verse 19. The crossing of the Valley of Arnon marked the entry of God's people into the Promised Land, particularly the part of it that was in the Transjordan. The Lord's command to provoke Sihon to war was a departure from previous instructions for the journey, where Israel was barred from attacking the neighbouring nations. But here for the first time, Israel is to begin to take possession
of the Promised Land.
24 ‘Rise up, set out on your journey and go over the Valley of the Arnon. Behold, I have given into your hand Sihon the Amorite, king of Heshbon, and his land. Begin to take possession, and contend with him in battle.