King David faces a deep moral dilemma, leading to a decision that highlights both his reverence for God and his immense respect for human life. The primary approach among commentators is that his refusal to drink the water stems directly from recognizing the severe mortal danger his warriors took upon themselves. Because these men risked their lives and faced death to retrieve it, David views the water as being equal to their blood. It is as if the lifeblood of the men is contained within the water itself.
Consequently, David feels it is entirely improper to consume water that was bought with blood. He explains that out of his awe of God, he cannot drink it, viewing the consumption of this water as an ordinary, everyday action that is forbidden to him under such heavy circumstances. Ultimately, this extraordinary act of risking their own lives is what secures the lasting fame and glory of these three warriors.