Abishai, the brother of Joab, he was chief of the three; for he lifted up his spear against three hundred and killed them, and had a name among the three.
And so he poured the water out on the ground because he just felt unworthy to drink that water. He felt that those guys that were willing to hazard their lives for a thing like that better that they give it to the Lord. So he poured it out to the Lord, verse eighteen.