2 Samuel 23:13-17

Then three of the thirty chief men went down and came to David at harvest time to the cave of Adullam, while the army of the Philistines was camping in the Valley of Rephaim.

David was then in the stronghold, while the garrison of the Philistines was then in Bethlehem.

And David had a craving and said, “Oh that someone would give me water to drink from the well of Bethlehem which is by the gate!”

So the three mighty men forced their way into the camp of the Philistines, and drew water from the well of Bethlehem which was by the gate, and carried it and brought it to David. Yet he would not drink it, but poured it out as an offering to the Lord;

and he said, “Far be it from me, Lord, that I would do this! Should I drink the blood of the men who went at the risk of their lives?” So he would not drink it. These things the three mighty men did.