1 Samuel 17:39

and David strapped his sword over his armor . And he tried in vain to go , for he had not tested them. Then David said to Saul , I cannot go with these , for I have not tested them. So David put them off .

David fastened on his sword over the tunic and tried walking around, because he was not used to them. “I cannot go in these,” he said to Saul, “because I am not used to them.” So he took them off.

And David girded his sword upon his armour, and he assayed to go; for he had not proved it . And David said unto Saul, I cannot go with these; for I have not proved them . And David put them off him.