Then Saul clothed David in his own tunic, put a bronze helmet on his head, and dressed him in armor.
David is at length presented to Saul for his champion (Sa1 17:31) and he bravely undertakes to fight the Philistine (Sa1 17:32): Let no man's heart fail because of him. It would have reflected too much upon the valour of his prince if he had said, Let not thy heart fail; therefore he speaks generally: Let no man's heart fail.
Commenting on 1 Samuel 17:31-39
And Saul armed David with his armour,.... Not with what he wore himself; for it cannot be thought he would strip himself of his armour in the field of battle, and when just going to it; and besides what suited the one would not be fit for the other, their bulk and stature being different i but this was some armour Saul had brought with...
Saul armed David with his armour--The ancient Hebrews were particularly attentive to the personal safety of their warriors, and hence Saul equipped the youthful champion with his own defensive accoutrements, which would be of the best style. It is probable that Saul's coat of mail, or corslet, was a loose shirt, otherwise it could not have fitted both a stripling and a man of the colossal stature of the king.