The excerpt below is entirely from Legend of the Jews, but is filled with too much tantalizing information to exclude.
“The crushing of those concealed in the caves of the mountain at Arnon was only the beginning of the miracles God wrought for Israel during their conquest of the land. It was at Arnon, too, that Sihon, the king of the Amorites, and his people who, hardly a month after Aaron's death, rushed upon Israel, were completely destroyed by them. This Amorite king, and likewise Og, the king of Bashan, were sons of Ahiah, whose father Shemhazai was one of the fallen angels. In accordance with his celestial origin Sihon was a giant who none could withstand, for he was of enormous stature, taller than any tower in all the world, his thigh-bone alone measuring eighteen cubits, according to the big cubit of that time. In spite of his huge size he was also fleet of foot, wherefore he was called Sihon, "foal," to indicate the celerity with which he moved, for his true name was Arad.
Moses was sorely afraid of waging war against this giant, but God put Sihon's and Og's guardian angels in chains, and then said to Moses: "Behold, I have begun to deliver up Sihon and his land before thee: begin to possess, that thou mayest inherit his land." For indeed after the angels of Sihon and his people had fallen, Moses had nothing more to fear, for his enemies were thus delivered into his hands. God assured Moses that "He would begin to put the dread of him and the fear of him upon the peoples that are under the whole heaven," by bidding the sun to stand still during his war against Sihon, that all the world might see that God battled for Moses.
Moses now asked if he might before waging war send ambassadors to Sihon to request him to permit Israel to pass through the land. God replied: "How now! I commanded thee, 'Rise up, contend with him in battle, begin to possess his land!' and thou wantest to send him messengers of peace?" Moses, however, replied: "I desire only to follow Thy example when Thou didst wish to lead Israel out of Egypt, and yet didst send me to Pharaoh with the message to let Israel, Thy people, pass out, even though Thou couldst have consumed all of Egypt with one flash of lightning. When Thou didst reveal the Torah, too, Thou didst offer it to the heathen nations for acceptance before giving it to Israel." God saw the justice of Moses' words, and commanded him never in the future to declare war upon a city before previously urging the people to surrender in peace.
Moses hereupon sent a missive to Sihon in which he requested him to permit Israel to pass through the land, promising him that he would see to it that the people should go along by the king's highway, so that he need have no cause to fear any deeds of violence upon married women, or seductions of girls. "We shall even," continued Moses, "pay for the water that is otherwise given freely, and likewise buy food-stuffs from thee at good prices." This letter to Sihon contained at its close, notwithstanding, the communication that the Israelites would bring war upon Sihon in case he did not permit them to pass through. Moses' assumption, however, that Sihon should permit Israel to pass through sounded in Sihon's ears like a summons to the keeper of a vineyard to permit one to harvest it. Sihon's answer therefore was as follows: "I and my brother Og receive tribute from all the other Canaanite kings to keep off their enemies from access to the land, and now you ask me to give you free access to Canaan!"
War between Sihon and Moses ensued, and ended in a brilliant victory for Israel. Sihon and his son, who equaled him in heroic strength, found their death in this fray. God had so brought it to pass that Israel had no need of laboriously waging war upon one city after another in Sihon's land, He had brought all the hosts of this Amorite king together into Heshbon. When this city therefore and the hosts within it were destroyed, all the rest of Sihon's land lay open before them. Israel's victory was all the more marvelous, because Heshbon was an exceptionally well fortified city, so that, had gnats been its inhabitants, it could not have been captured by mortal means, much less so when manned by the hero Sihon and his heroic warriors. This victory was made possible only by the fact that God visited them with convulsions so terrible that they rolled up and writhed in pain, unable to stand in the battle lines, so that Israel could cut them down while they were half dead from convulsive pains. God also drew masks over their faces, so that they could not see plainly, and taking one another for Israelites, slew their own people.
With the fall of Heshbon Israel came into possession of all the land of Sihon, with the exception of Jazer, and Moses therefore sent spies to that city. The men whom he sent there, Caleb and Phinehas, were not only capable warriors, but also pious men. They said: "Moses once sent spies who brought great misfortune upon all their generations, we will attack this city, trusting in God, and we are sure we shall not perish, because Moses has prayed for our welfare." They thereupon attacked Jazer, conquered it, and when upon the day after Moses had sent them out they returned to him, they informed him that they had conquered Jazer and slain its inhabitants.”1
“Og met his death in the following fashion. When he discovered that Israel's camp was three parasangs in circumference, he said: "I shall now tear up a mountain of three parasangs, and cast it upon Israel's camp, and crush them." He did as he had planned, pulled up a mountain of three parasangs, laid it upon his head, and came marching in the direction of the Israelite camp, to hurl it upon them. But what did God do? He caused ants to perforate the mountain, so that is slipped from Og's head down upon his neck, and when he attempted to shake it off, he teeth pushed out and extended to left and right, and did not let the mountain pass, so that he now stood there with the mountain, unable to throw it from him. When Moses saw this, he took an axe twelve cubits long, leaped ten cubits into the air, and dealt a blow to Og's ankle, which caused the giant's death.
This was the end of the last of the giants, who was not only last in time, but also in significance, for despite his height and strength, he was the most insignificant of the giants who perished in the flood.
With Og's death all his lands fell to the lot of the Israelites without another sword's stroke, for God has so ordained it that all of Og's warriors were with him at his encounter with Israel, and after Israel had conquered these, only women and children remained in all the land. Had Israel been obliged to advance upon every city individually, they would never have finished, on account of the number of the cities and the strength of the hosts of the Amorites.
Not alone Sihon and Og, the kings of the Amorites, were such giants and heroes, but all the Amorites. When Hadrian conquered Jerusalem, he boasted of his victory, whereupon Rabba Johanan, the son of Zakkai, said to hi: "Boast not of thy victory over Jerusalem, for, had not God conquered it for thee, thou shouldst never have gained it." He thereupon led Hadrian to a cave where he showed him the corpses of the Amorites, each of which was eighteen cubits, and said: "When we were worthy of victory, these fell into our hands, but now, on account of our sins, dost thou rule over us."
The victory over Sihon and his hosts was as great as that over Pharaoh and his hosts, and so was the victory over Og and his hosts. Each of these victories was as important as that over the thirty-one kings that Joshua later captured, and it would well have behooved Israel to sing songs of praise to their Lord as after Pharaoh's destruction. David later made good this omission, for he intoned a song of praise in gratitude for the victory God had lent to Israel over Sihon and Og.
Without direct assistance from God these victories would not have been possible, but He sent hornets upon them, and their destruction was irrevocable. Two hornets pursued ever Amorite; one bit one eye, the second the other eye, and the poison of these little creatures consumed those bitten by them. These hornets remained on the east side of the Jordan, and did not pursue Israel's march to the regions west of the Jordan, nevertheless they wrought great havoc among the Canaanites of the region west of the Jordan. The hornets stood on the eastern bank of the Jordan, and spat their venom across to the opposite bank, so that the Canaanites that were hit became blind and were disarmed.
When God promised Moses to send an angel to Israel, he declined the offer with the words: "If Thy presence go not with me, carry us not up hence," whereupon God replied: "Thou complainest because I desire to send only an angel to assist thee to conquer the land. As truly as thou livest, I shall now send thee not even an angel, but a hornet to destroy the enemies of Israel. It is, however, for thy sake alone that I deliver the enemy into Israel's hands, and not as if Israel deserved it through their own good deeds."
Og's bed, fashioned out of ivory, that measured nine arms' length, taking the giant's arm as a standard, Og had preserved in the Ammonite city Rabbah, for he knew that Israel would penetrate neither to the land of the Ammonites nor of the Moabites, because God had prohibited them from coming too close to Lot's descendants. He likewise forbade them to wage war with the Edomites; in this way Esau, a son kind to his father Isaac, was rewarded by not having his descendants, the Edomites, molested by Israel. God said to Israel: "In this world ye shall have no sway over the mountain Seir, Edom's realm, but in the future world, when ye shall be released, then shall ye obtain possession of it. Until then, however, beware of the sons of Esau, even when they fear ye, much more so when ye shall dwell scattered among them.”2
More about Moses’s attack on Og from Rabbeinu Bahya ben Asher:
“We are told in Berachot 54 that Moses who was 10 cubits tall (one cubit taller than Og) took a ten cubit-long axe and jumped ten cubits into the air and killed Og with it. The wording in the Talmud appears to be an allusion to Moses having countered the merit of Og and the reward he had received for making an effort with his feet at the time when he informed Avraham of Lot’s capture. The author credits his teacher the Rashba with the following aggadic explanation: The Talmud writes this passage (in Berachot) only so that we should not think that Moses’ fear of Og concerned Og’s physique, his prowess as a warrior. Enjoying G’d’s grace is totally independent of one’s physique and physical strength. G’d relates to people in relation to the merits they have accumulated. We have this on the authority of Psalms 147, 10-11: “He does not prize the strength of horses, nor value the fleetness of men; but the Lord values those who fear Him, those who depend on His faithful care.”3
Legend of the Jews, 3:5:91
Legend of the Jews, 3:5:98
Rabbeinu Bahya, Bamidbar 21:34:5