1 Samuel 17

1 Samuel 17:49

David never waged war unless he was driven to it. Thus prudence was combined in him with fortitude in the battle. For even when about to fight single-handed against Goliath, the enormous giant, he rejected the armor with which he was laden. His strength depended more on his own arm than on the weapons of others. Then, at a distance, to get a stronger throw, with one cast of a stone, he killed his enemy. — On the Duties of the Clergy 1.35.177