David was the youngest. The three eldest followed Saul,
Forty days the two armies lay encamped facing one another, each advantageously posted, but neither forward to engage. Either they were parleying and treating of an accommodation or they were waiting for recruits; and perhaps there were frequent skirmishes between small detached parties.
Commenting on 1 Samuel 17:12-30
And David was the youngest,.... For the sake of whom this account is given of Jesse and his family, and who after this makes a considerable figure in the camp and court of Saul: and the three eldest followed Saul; as before related, and which is repeated, that it might be observed that they only of Jesse's sons followed Saul; not David particularly, but who...
1Sa 17:12-15 1Sa 17:12-15 are closely connected with the preceding words, “All Israel was alarmed at the challenge of the Philistine; but David the son of that Ephratite (Ephratite, as in Rth 1:1-2) of Bethlehem in Judah, whose name was Jesse,” etc. The verb and predicate do not follow till 1Sa 17:15; so that the words occur here in the form of an anacolouthon.
Commenting on 1 Samuel 17:12-15