1 Samuel 17:14

But, as for David, he, was the youngest, - and, the three eldest, followed Saul;

1 Samuel 16:11

Then said Samuel unto Jesse - Are these all the young men? And he said - There yet remaineth, the youngest, but lo! he is tending the sheep. Then said Samuel unto Jesse - Do, send, and summon him, for we cannot sit round, until he cometh in hither.

Genesis 25:23

And Yahweh said to her. Two nations, are in thy womb, And two races, from thy body, shall be parted, - And, one race, shall be stronger, than the other race, And the elder, shall serve the younger.

Treasury of Scripture Knowledge

Summary

And David was the youngest: and the three eldest followed Saul.

Bible References

The youngest

1 Samuel 16:11
Then said Samuel unto Jesse - Are these all the young men? And he said - There yet remaineth, the youngest, but lo! he is tending the sheep. Then said Samuel unto Jesse - Do, send, and summon him, for we cannot sit round, until he cometh in hither.
Genesis 25:23
And Yahweh said to her. Two nations, are in thy womb, And two races, from thy body, shall be parted, - And, one race, shall be stronger, than the other race, And the elder, shall serve the younger.