I cannot go with these - In ancient times it required considerable exercise and training to make a man expert in the use of such heavy armor; armor which in the present day scarcely a man is to be found who is able to carry; and so it must have been then, until that practice which arises from frequent use had made the proprietor perfect. I have not proved them says David: I am wholly unaccustomed to such armor and it would be an encumbrance to me.

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 (i); 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.

(i) Homer. Iliad. 19. ver. 384, 385. so Theocrit. Idyll. 10. ver. 61.

When he was thus equipped with brazen helmet, coat of mail, and sword, David began to walk, but soon found that he could do nothing with these. He therefore said to Saul, "I cannot go in these things, for I have not tried them;" and having taken them off, he took his shepherd's staff in his hand, sought out five smooth stones from the brook-valley, and put them in the shepherd's thing that he had, namely his shepherd's bag. He then took the sling in his hand, and went up to the Philistine. In the exercise of his shepherd's calling he may have become so skilled in the use of the sling, that, like the Benjaminites mentioned in Judges 20:16, he could sling at a hair's-breadth, and not miss.

And David girded his sword upon his armor, 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.

17:39 Proved them - I have no skill or experience in the managements of this kind of arms.

17:31-39 A shepherd lad, come the same morning from keeping sheep, had more courage than all the mighty men of Israel. Thus God often sends good words to his Israel, and does great things for them, by the weak and foolish things of the world. As he had answered his brother's passion with meekness, so David answered Saul's fear with faith. When David kept sheep, he proved himself very careful and tender of his flock. This reminds us of Christ, the good Shepherd, who not only ventured, but laid down his life for the sheep. Our experience ought to encourage us to trust in God, and be bold in the way of duty. He that has delivered, does and will continue to do so. David gained leave to fight the Philistine. Not being used to such armour as Saul put upon him, he was not satisfied to go in that manner; this was from the Lord, that it might more plainly appear he fought and conquered in faith, and that the victory was from Him who works by the feeblest and most despised means and instruments. It is not to be inquired how excellent any thing is, but how proper. Let Saul's coat be ever so rich, and his armour ever so strong, what is David the better if they fit him not? But faith, prayer, truth, and righteousness; the whole armour of God, and the mind that was in Christ; are equally needful for all the servants of the Lord, whatever may be their work.