20 Benaiah was the son of Jehoiada, the son of a valiant man from Kabzeel, who had done many deeds. He had killed two lion-like heroes of Moab. He also had gone down and killed a lion in the midst of a pit on a snowy day. 21 And he killed an Egyptian, a spectacular man. The Egyptian had a spear in his hand; so he went down to him with a staff, wrested the spear out of the Egyptian's hand, and killed him with his own spear 22 These things Benaiah the son of Jehoiada did, and won a name among three mighty men. 23 He was more honored than the thirty, but he did not attain to the first three. And David appointed him over his guard.
Matthew Henry's Commentary on 2 Samuel 23:20-23
Commentary on 2 Samuel 23:8-39
(Read 2 Samuel 23:8-39)
David once earnestly longed for the water at the well of Bethlehem. It seems to be an instance of weakness. He was thirsty; with the water of that well he had often refreshed himself when a youth, and it was without due thought that he desired it. Were his valiant men so forward to expose themselves, upon the least hint of their prince's mind, and so eager to please him, and shall not we long to approve ourselves to our Lord Jesus, by ready compliance with his will, as shown us by his word, Spirit, and providence? But David poured out the water as a drink-offering to the Lord. Thus he would cross his own foolish fancy, and punish himself for indulging it, and show that he had sober thoughts to correct his rash ones, and knew how to deny himself. Did David look upon that water as very precious which was got at the hazard of these men's blood, and shall not we much more value those benefits for purchasing which our blessed Saviour shed his blood? Let all beware of neglecting so great salvation.