14 David was then in the stronghold, and the garrison of the Philistines was then in Bethlehem 15 And David said with longing, "Oh, that someone would give me a drink of the water from the well of Bethlehem, which is by the gate!" 16 So the three mighty men broke through the camp of the Philistines, drew water from the well of Bethlehem that was by the gate, and took it and brought it to David. Nevertheless he would not drink it, but poured it out to the Lord. 17 And he said, "Far be it from me, O Lord, that I should do this! Is this not the blood of the men who went in jeopardy of their lives?" Therefore he would not drink it. These things were done by the three mighty men.
Matthew Henry's Commentary on 2 Samuel 23:14-17
Commentary on 2 Samuel 23:8-39
(Read 2 Samuel 23:8-39)
David once earnestly longed for the water at the well of Bethlehem. It seems to be an instance of weakness. He was thirsty; with the water of that well he had often refreshed himself when a youth, and it was without due thought that he desired it. Were his valiant men so forward to expose themselves, upon the least hint of their prince's mind, and so eager to please him, and shall not we long to approve ourselves to our Lord Jesus, by ready compliance with his will, as shown us by his word, Spirit, and providence? But David poured out the water as a drink-offering to the Lord. Thus he would cross his own foolish fancy, and punish himself for indulging it, and show that he had sober thoughts to correct his rash ones, and knew how to deny himself. Did David look upon that water as very precious which was got at the hazard of these men's blood, and shall not we much more value those benefits for purchasing which our blessed Saviour shed his blood? Let all beware of neglecting so great salvation.