Costly drink

1 Chronicles 11:15 Three of the thirty chief men went down to the rock to David at the cave of Adullam, when the army of Philistines was encamped in the Valley of Rephaim. David was then in the stronghold, and the garrison of the Philistines was then at Bethlehem. And David said longingly, “Oh that someone would give me water to drink from the well of Bethlehem that is by the gate!” Then the three mighty men broke through the camp of the Philistines and drew water out of the well of Bethlehem that was by the gate and took it and brought it to David. But David would not drink it. He poured it out to the Lord and said, “Far be it from me before my God that I should do this. Shall I drink the lifeblood of these men? For at the risk of their lives they brought it.” Therefore he would not drink it. These things did the three mighty men.

 The ESV Study Bible makes this comment:

This may at first seem wasteful of David, and ungrateful, but it is a gesture showing great value. He likens the water to the blood of his men, and for David to drink the water obtained at the risk of their lives would have been to take their blood lightly. But to pour it out before the Lord was a way of saying that he was not worthy of it, and he was offering it to the Lord instead. Such “drink offerings” were often poured out before the Lord: see Gen. 35:14Num. 15:7–10; 28:7–15; etc.