Thou art but a youth - Supposed to be about twenty-two or twenty-three years of age.

And Saul said to David, thou art not able to go against this Philistine to fight with him,.... Had neither strength of body, nor skill in military affairs, to encounter with a man of his stature, and warlike genius and practice:

for thou art but a youth; some say about fourteen or sixteen years of age, but very probably about twenty, and not more, and so not only weak, but inexpert in the art of fighting:

and he a man of war from his youth; a gigantic man, trained up in, inured to, and expert in the affairs of war; so that David could not, on any account, be a competitor with him, and a match for him.

To Saul's objection that he, a mere youth, could not fight with this Philistine, a man of war from his youth up, David replied, that as a shepherd he had taken a sheep out of the jaws of a lion and a bear, and had also slain them both. The article before ארי and דּוב points out these animals as the well-known beasts of prey. By the expression ואת־הדּוב the bear is subordinated to the lion, or rather placed afterwards, as something which came in addition to it; so that את is to be taken as a nota accus. (vid., Ewald, 277, a), though it is not to be understood as implying that the lion and the bear went together in search of prey. The subordination or addition is merely a logical one: not only the lion, but also the bear, which seized the sheep, did David slay. זה, which we find in most of the editions since the time of Jac. Chayim, 1525, is an error in writing, or more correctly in hearing, for שׂה, a sheep. "And I went out after it; and when it rose up against me, I seized it by its beard, and smote it, and killed it." זקן, beard and chin, signifies the bearded chin. Thenius proposes, though without any necessity, to alter בּזקנו into בּגרונו, for the simple but weak reason, that neither lions nor bears have any actual beard. We have only to think, for example, of the λῖς ἠυγένειος in Homer (Il. xv. 275, xvii. 109), or the barbam vellere mortuo leoni of Martial (x. 9). Even in modern times we read of lions having been killed by Arabs with a stick (see Rosenmller, Bibl. Althk. iv. 2, pp. 132-3). The constant use of the singular suffix is sufficient to show, that when David speaks of the lion and the bear, he connects together two different events, which took place at different times, and then proceeds to state how he smote both the one and the other of the two beasts of prey.

And Saul said to David, Thou art not {k} able to go against this Philistine to fight with him: for thou art but a youth, and he a man of war from his youth.

(k) Here Satan proves David's faith, by the infidelity of Saul.

17:33 A youth - Not above 20 years old; and a novice, a raw and unexperienced soldier.

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.