1 Samuel 26:6
Then answered David and said to Ahimelech the Hittite, and to Abishai the son of Zeruiah, brother to Joab, saying, Who will go down with me to Saul to the camp? And Abishai said, I will go down with thee. Then answered David and said to Ahimelech the Hittite, and to Abishai the son of Zeruiah, brother to Joab, saying, Who will go down with me to Saul to the camp? And Abishai said, I will go down with thee.
David was at this time a fugitive hunted by Saul, having no place of rest or security, after Abiathar had escaped to him following Saul's slaughter of the priests. The immediate setting was night, after Saul had once again marched in pursuit of David on information from the Ziphites about David's hiding place.
David had learned Saul's whereabouts through friendly spies and had advanced cautiously with a few of his men to locate the enemy. Coming upon the tents of the king and his attendants, he found them quiet in slumber while he himself remained unobserved. From that vantage he asked his companions for someone to go down with him into the very midst of the hostile camp.
Abishai promptly volunteered to go with him, and the two entered together hidden by the deep shadows of the hills.