And David girded his, sword upon his armour
 Which Saul also perhaps furnished him with: 
 and he assayed to go;
 made an attempt, and had a mind to go thus accoutred; he at first showed an inclination to go in such an habit, but afterwards would not: 
 for he had not proved [it];
 as warriors were wont to do; so Achilles did F9; he never made trial of such armour before, he had not been used to it, and knew not how to behave in it, or walk with it on him; it was an encumbrance to him: Abarbinel renders it, "but he had not proved [it]"; he would have gone with it but for that reason; the Targum is, 
``because there was no miracle in them;''because if he had made use of this, there would have been no appearance of a miracle in getting the victory over the Philistine, as was by using only a sling and stones:
 and David said unto Saul, I cannot go with these, for I have not proved
 [them];
 he thought fit to acquaint Saul with it that he could not go thus accoutred, and his reason for it, lest he should be offended with him: 
 and David put them off him;
 took off the helmet from his head, ungirt the sword upon his armour, and stripped himself of his coat of mail, and went forth entirely unarmed.