Deuteronomy 2:26-30. Moses is recounting how he asked the king of Heshbon to allow him and the people to pass through that land on their way to the Jordan. Moses promised they would pass through only, not turning left or right, and would pay for their food and water as they were in Heshpon. "But Sihon the king of Heshbon would not let us pass by him; for the Lord your God hardened his spirit and made his heart obstinate, that he might give him into your hand."

God's will is always done, often in ways we just do not understand and can seem very contrary to us, and often in ways that make us  fight harder than we might think we sould have to. Just as when God kept sending Moses to Pharaoh to ask for the people's freedom and God kept hardening Pharaoh's heart, so here God hardened Sihon's heart against the Jews. Other leaders had let the Jews pass through their lands, Sihon knew that and knew that the Jews had caused no trouble there, yet he still refused to let them pass. Ultimately, this led to his defeat and to the land being given to the Jews.

At the time Pharaoh and Sihon said no to Moses, it must have seemed so frustrating and unreasonable to Moses - God kept asking Moses to do things but Moses was not getting the results that God seemingly wanted, instead he met with human resistance. But the more times this happened to Moses, I'm sure that he realized the way that God worked, and that when he didn't get the answer right away, something better was probably coming.

God hardens the hearts of certain people in order to not only make us work harder so that we appreciate what He's giving us but also because He is going to be giving us a much better thing than we are asking for. If God wanted his people to pass through Heshbon only, they would have - Sihon's heart would not have been hardened. Instead, God wanted his people to possess Heshbon. He could have just given it to them through his own power, but God always wants us to work with Him so that we appreciate his gifts, so He hardened Cheyenne's heart and made His people have to fight for the prize He wanted to give them.