ABISHAI , the son of Zeruiah, brother of *Joab and *Asahel and nephew of David. Abishai was one of David's most loyal military officers. He was one of David's three mighty men and is credited with killing 300 people (ii Sam. 23:18). Additionally, he is said to have been the head of this group, and according to some versions he was the head of the thirty heroes (ii Sam. 23:18; i Chron. 11:20). Abishai was one of the three generals who defeated Ish-Bosheth, Saul's son, and Abner, the commander of Saul's army. After the battle Abner killed Asahel (ii Sam. 2:18 ff.). According to ii Samuel 3:30, Abishai and his brother Joab eventually avenged their brother's death. However, the Septuagint apparently did not hold them responsible for this murder, reading 'arevu ("lie in wait") instead of haregu ("killed") of the masoretic text. David, nevertheless, certainly thought both of them guilty (ii Sam. 3:39). Abishai defeated the Canaanite confederation against David (ii Sam. 10), and during Absalom's revolt he commanded one-third of David's forces (ii Sam. 18:2). Additionally, he was instrumental in suppressing Sheba, the son of Bichri (ii Sam. 20:6–10). He was also one of David's leading generals in other wars with the Philistines (ii Sam. 21:15–17) and the Edomites (i Chron. 18:12); he rescued David at Nob from the threats of a Philistine giant, who has been referred to in some sources as Ishbibenob (ii Sam. 21:16–17); and he was against the king's policy of making peace with his enemies (ii Sam. 16:9–10, 19:23). Abishai's suggestion to kill Saul in his camp was refused by David (i Sam. 26:6 ff.).
In the Aggadah
Abishai's rescue of David (ii Sam. 21:16–17) illustrates his piety and valor. David had been enticed over the Philistine border by Satan and there seized by Ishbibenob, the brother of Goliath. This was miraculously revealed to Abishai while he was bathing in preparation for the Sabbath. He was aided in his search for David by the fact that the earth contracted under him. On his way he encountered and slew Orpah. When Ishbibenob saw him approaching, he planted his spear in the ground and threw David up in the air saying: "Let him fall on it and perish." Abishai, however, pronounced the Divine Name, and David remained suspended in the air until he descended safely in answer to a prayer of Abishai. Abishai and David foiled the final attack of the enraged giant by weakening him with taunts about his mother's death at Abishai's hands (Sanh. 95a). Abishai was equal to 70,000 men of Israel (Mid. Ps. 17:4).
D. Schley, abd 1:24–6.
"Abishai." Encyclopaedia Judaica. . Encyclopedia.com. (September 26, 2018). http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/abishai
"Abishai." Encyclopaedia Judaica. . Retrieved September 26, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/abishai