In 1 Samuel 26:6, it is mentioned: "Then David said to Ahimelech the Hittite and to Abishai the son of Zeruiah, Joab's brother, 'Who will go down with me into the camp to Saul?' And Abishai said, 'I will go down with you.'"

So, Abishai is the one who accompanied Saul in the search for David in the wilderness of Ziph according to the biblical account.