1 Samuel 17:38-39

38Saul took his own clothes and armour and he put them on David. He put his bronze helmet on David's head.

39David tied Saul's sword on top of the armour. Then he tried to walk. But he had not worn heavy armour like that before. So David said to Saul, ‘I cannot wear all this armour to fight. I have not used armour before.’ So David took it all off.