 God instructed the Israelites to set out across the wadi Arnon, to attack Sihon the Amorite, king of Heshbon, and begin to occupy his land.Moses sent messengers to King Sihon with an offer of peace, asking for passage through his country, promising to keep strictly to the highway, turning neither to the right nor the left, and offering to purchase what food and water they would eat and drink.But King Sihon refused to let the Israelites pass through, because God had stiffened his will and hardened his heart in order to deliver him to the Israelites.