New Revised Standard Version
Saul said to David, “You are not able to go against this Philistine to fight with him; for you are just a boy, and he has been a warrior from his youth.”

Contemporary English Version
"You don't have a chance against him," Saul replied. "You're only a boy, and he's been a soldier all his life."

New American Bible
But Saul answered David, “You cannot go up against this Philistine and fight with him, for you are only a youth, while he has been a warrior from his youth.”

Douay-Rheims Bible
And Saul said to David: Thou art not able to withstand this Philistine, nor to fight against him: for thou art but a boy, but he is a warrior from his youth.

And Saul said to David: Thou art not able to withstand this Philistine, nor to fight against him: for thou art but a boy, but he is a warrior from his youth.

Thou art not

Numbers 13:31 But the others, that had been with him, said: No, we are not able to go up to this people, because they are stronger than we.

Deuteronomy 9:2 A people great and tall, the sons of the Enacims, whom thou hast seen, and heard of, against whom no man is able to stand.

Psalm 11:1 Unto the end. A psalm to David.

Revelation 13:4 And they adored the dragon which gave power to the beast. And they adored the beast, saying: Who is like to the beast? And who shall be able to fight with him?

for thou are but

1 Samuel 17:42,56 And when the Philistine looked, and beheld David, he despised him. For he was a young man, ruddy, and of a comely countenance. . . .