Numbers 21:29-35 … warring the giants

²⁹ Woe to thee, Moab! thou art undone, O people of Chemosh: he hath given his sons that escaped, and his daughters, into captivity unto Sihon (tempestuous) king of the Amorites.

³⁰ We have shot at them; Heshbon is perished even unto Dibon, and we have laid them waste even unto Nophah, which reacheth unto Medeba.

³¹ Thus Israel dwelt in the land of the Amorites.

³² And Moses sent to spy out Jaazer, and they took the villages thereof, and drove out the Amorites that were there.

³³ And they turned and went up by the way of Bashan: and Og the king of Bashan went out against them, he, and all his people, to the battle at Edrei.

³⁴ And the Lord said unto Moses, Fear him not: for I have delivered him into thy hand, and all his people, and his land; and thou shalt do to him as thou didst unto Sihon king of the Amorites, which dwelt at Heshbon.

³⁵ So they smote him, and his sons, and all his people, until there was none left him alive: and they possessed his land. (These were Nephilim giants)

• Deuteronomy 2:24-35 “Rise ye up, take your journey, and pass over the river Arnon: behold, I have given into thine hand Sihon the Amorite, king of Heshbon, and his land: begin to possess it, and contend with him in battle. This day will I begin to put the dread of thee and the fear of thee upon the nations that are under the whole heaven, who shall hear report of thee, and shall tremble, and be in anguish because of thee. And I sent messengers out of the wilderness of Kedemoth unto Sihon king of Heshbon with words of peace, saying, Let me pass through thy land: I will go along by the highway, I will neither turn unto the right hand nor to the left. Thou shalt sell me meat for money, that I may eat; and give me water for money, that I may drink: only I will pass through on my feet; (As the children of Esau which dwell in Seir, and the Moabites which dwell in Ar, did unto me;) until I shall pass over Jordan into the land which the Lord our God giveth us. But Sihon king of Heshbon would not let us pass by him: for the Lord thy God hardened his spirit, and made his heart obstinate, that he might deliver him into thy hand, as appeareth this day. And the Lord said unto me, Behold, I have begun to give Sihon and his land before thee: begin to possess, that thou mayest inherit his land. Then Sihon came out against us, he and all his people, to fight at Jahaz. And the Lord our God delivered him before us; and we smote him, and his sons, and all his people.”
• And we took all his cities at that time, and utterly destroyed the men, and the women, and the little ones, of every city, we left none to remain: Only the cattle we took for a prey unto ourselves, and the spoil of the cities which we took. From Aroer, which is by the brink of the river of Arnon, and from the city that is by the river, even unto Gilead, there was not one city too strong for us: the Lord our God delivered all unto us: Only unto the land of the children of Ammon thou camest not, nor unto any place of the river Jabbok, nor unto the cities in the mountains, nor unto whatsoever the Lord our God forbad us. Then we turned, and went up the way to Bashan: and Og the king of Bashan came out against us, he and all his people, to battle at Edrei. And the Lord said unto me, Fear him not: for I will deliver him, and all his people, and his land, into thy hand; and thou shalt do unto him as thou didst unto Sihon king of the Amorites, which dwelt at Heshbon. So the Lord our God delivered into our hands Og also, the king of Bashan, and all his people: and we smote him until none was left to him remaining. And we took all his cities at that time, there was not a city which we took not from them, threescore cities, all the region of Argob, the kingdom of Og in Bashan. All these cities were fenced with high walls, gates, and bars; beside unwalled towns a great many.”

Notice this was no small order. The inhabitants of Bashan were well trained, well armed and prepared for this sort of event.