Abishai was David's sister Zeruiah's boy. His brother was Joab. Abishai had the well earned honor of being named "Chief of the Three." The Bible says, "He raised his spear against three hundred men, whom he killed, and so he became as famous as the Three." Interesting tidbit, the Bible also says, "Was he not held in greater honor than the Three? He became their commander, even though he was not included among them."
So he was own department. He was more special than the thirty and even more special than the Three. Did his bravery earn him his title? Probably so. His methods weren't always what we would call honorable, he did want to help David kill a sleeping King Saul. (1 Samuel 26:6-9). He helped his brother Joab in the revenge murder of Abner, who had killed their brother Asahel (2 Samuel 3:30). He wasn't one to let criticism of his family go unpunished when he told David he would cut off Shimei's head for criticizing his uncle. (2 Samuel 16:1-14).
One of the last acts he committed on David's behalf, perhaps with the memory of David himself killing Goliath as a young teenager, a giant whose armor was too heavy for a young David to wear, was repeated when Abishai struck down Ishbi-Benonb, whose bronze spearhead alone weighed 7 1/2 pounds.
Fearlessness seemed to run in Abishai's blood. The influence David had on Abishai most likely went unnoticed by David, but Abishai seemed to have kept mental notes of a brave uncle, a fearless leader in the making, running towards a giant.
Abishai was courageous and loyal. Chief of the Three, a Mighty Man who stood alone as he fought for his uncle the King.
A is for Abishai.