Albert Barnes Commentary 2 Samuel 23:17

"And he said, Be it far from me, O Jehovah, that I should do this: [shall I drink] the blood of the men that went in jeopardy of their lives? therefore he would not drink it. These things did the three mighty men." — 2 Samuel 23:17 (ASV)

This is better understood by comparing it to 1 Chronicles 11:19.