1 Samuel 17:38-40 AMPC
Then Saul clothed David with his armor; he put a bronze helmet on his head and clothed him with a coat of mail.
And David girded his sword over his armor. Then he tried to go, but could not, for he was not used to it. And David said to Saul, I cannot go with these, for I am not used to them. And David took them off.
Then he took his staff in his hand and chose five smooth stones out of the brook and put them in his shepherd's [lunch] bag [a whole kid's skin slung from his shoulder], in his pouch, and his sling was in his hand, and he drew near the Philistine.
AMPC: Amplified Bible, Classic Edition