1 Samuel 24:4

And the men of David said unto him, for they could plainly see Saul, as they looked toward the light, while Saul's eyes could not penetrate the darkness in the rear, Behold the day of which the Lord said unto thee, Behold, I will deliver thine enemy into thine hand, that thou mayest do to him as it shall seem good unto thee. Their reference seems to be only to what they considered a divine ordering of this favorable opportunity to take revenge upon Saul. Then David arose, and cut off the skirt of Saul's robe privily, a corner of his upper garment, which Saul had evidently laid aside.