1 Samuel 26:17
And Saul knew David’s voice, and said, Is this thy voice, my son David? And David said, It is my voice, my lord, O king. And Saul knew David’s voice, and said, Is this thy voice, my son David? And David said, It is my voice, my lord, O king.
The exchange belongs to the time when David was a fugitive hunted by Saul, in the history covered by 1 Samuel 23-27. Shortly before, after Saul slaughtered the Lord's priests, Abiathar son of Ahimelech escaped to David, and David received him with promise of safeguard because Saul sought both their lives. The words follow David's second sparing of Saul's life, when he took the king's spear and cruse of water from beside his head at his bolster. From a safe distance on a hilltop he then called with a loud voice to Abner and the people to prove their failure to guard the Lord's anointed.
Saul recognized David's voice and asked if it was his, calling him my son David, and David confirmed it was his voice while addressing Saul as my lord and king. That answer opened David's plea of innocence and Saul's more humble acknowledgment of fault. This second respect for his sovereign's life made a still deeper impression on Saul, astonishing and subduing him with such kindness. Even so, David had no hope that the king would long continue in that repentant frame of mind and was unwilling to place himself again in his power.