Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[9] But as soon as Abner, the son of Ner, who was general of Saul's army, and a very active man, and good-natured, knew that the king, and Jonathan, and his two other sons, were fallen in the battle, he made haste into the camp; and taking away with him the remaining son of Saul, whose name was Ishbosheth, he passed over to the land beyond Jordan, and ordained him the king of the whole multitude, excepting the tribe of Judah; and made his royal seat in a place called in our own language Mahanaim, but in the language of the Grecians, The Camps; from whence Abner made haste with a select body of soldiers, to fight with such of the tribe of Judah as were disposed to it, for he was angry that this tribe had set up David for their king. But Joab, whose father was Suri, and his mother Zeruiah, David's sister, who was general of David's army, met him, according to David's appointment. He had with him his brethren, Abistiai and Asahel, as also all David's armed men. Now when he met Abner at a certain fountain, in the city of Gibeon, he prepared to fight. And when Abner said to him, that he had a mind to know which of them had the more valiant soldiers, it was agreed between them that twelve soldiers of each side should fight together. So those that were chosen out by both the generals for this fight came between the two armies, and throwing their lances one against the other, they drew their swords, and catching one another by the head, they held one another fast, and ran each other's swords into their sides and groins, until they all, as it were by mutual agreement, perished together. When these were fallen down dead, the rest of the army came to a sore battle, and Abner's men were beaten; and when they were beaten, Joab did not leave off pursuing them, but he pressed upon them, and excited the soldiers to follow them close, and not to grow weary of killing them. His brethren also pursued them with great alacrity, especially the younger, Asahel, who was the most eminent of them. He was very famous for his swiftness of foot, for he could not only be too hard for men, but is reported to have overrun a horse, when they had a race together. This Asahel ran violently after Abner, and would not turn in the least out of the straight way, either to the one side or to the other. Hereupon Abner turned back, and attempted artfully to avoid his violence. Sometimes he bade him leave off the pursuit, and take the armor of one of his soldiers; and sometimes, when he could not persuade him so to do, he exhorted him to restrain himself, and not to pursue him any longer, lest he should force him to kill him, and he should then not be able to look his brother in the face: but when Asahel would not admit of any persuasions, but still continued to pursue him, Abner smote him with his spear, as he held it in his flight, and that by a back-stroke, and gave him a deadly wound, so that he died immediately; but those that were with him pursuing Abner, when they came to the place where Asahel lay, they stood round about the dead body, and left off the pursuit of the enemy. However, both Joab ¹ himself, and his brother Abishai, ran past the dead corpse, and making their anger at the death of Asahel an occasion of greater zeal against Abner, they went on with incredible haste and alacrity, and pursued Abner to a certain place called Ammah: it was about sun-set. Then did Joab ascend a certain hill, as he stood at that place, having the tribe of Benjamin with him, whence he took a view of them, and of Abner also. Hereupon Abner cried aloud, and said that it was not fit that they should irritate men of the same nation to fight so bitterly one against another; that as for Asahel his brother, he was himself in the wrong, when he would not be advised by him not to pursue him any farther, which was the occasion of his wounding and death. So Joab consented to what he said, and accepted these his words as an excuse [about Asahel], and called the soldiers back with the sound of the trumpet, as a signal for their retreat, and thereby put a stop to any further pursuit. After which Joab pitched his camp there that night; but Abner marched all that night, and passed over the river Jordan, and came to Ishbosheth, Saul's son, to Mahanaim. On the next day Joab counted the dead men, and took care of all their funerals. Now there were slain of Abner's soldiers about three hundred and sixty; but of those of David nineteen, and Asahel, whose body Joab and Abishai carried to Bethlehem; and when they had buried him in the sepulcher of their fathers, they came to David to Hebron. From this time therefore there began an intestine war, which lasted a great while, in which the followers of David grew stronger in the dangers they underwent, and the servants and subjects of Saul's sons did almost every day become weaker.