1 Samuel 24:16
And it came to pass, when David had made an end of speaking these words unto Saul, that Saul said, Is this thy voice, my son David? And Saul lifted up his voice, and wept. And it came to pass, when David had made an end of speaking these words unto Saul, that Saul said, Is this thy voice, my son David? And Saul lifted up his voice, and wept.
The scene is a confrontation between David, still a shepherd youth though already holding God's promise of the throne, and Saul, the established monarch determined to retain his power.
Saul was deeply moved as he heard David speak and recognized that David had spared his life when he had the opportunity to kill him. His question about whether this was David's voice and his lifting up his voice in weeping were a humbled admission of David's innocence and restraint.