1 Samuel 17:37-39 New English Translation (NET Bible)
37 David went on to say, “The Lord who delivered me from the lion and the bear will also deliver me from the hand of this Philistine!” Then Saul said to David, “Go! The Lord will be with you.”
38 Then Saul clothed David with his own fighting attire and put a bronze helmet on his head. He also put body armor on him. 39 David strapped on his sword over his fighting attire and tried to walk around, but he was not used to them. David said to Saul, “I can’t walk in these things, for I’m not used to them.” So David removed them.