1 Samuel 17:14

And David was the youngest. And when the three eldest were gone after Saul,

1 Samuel 16:11

Then said Samuel to Jesse, "Are here all thy children?" And he said, "The youngest is yet behind. Behold, he keepeth the sheep." Then Samuel said unto Jesse, "Send and fetch him for we will not sit down, till he be come hither."

Genesis 25:23

And the LORD said unto her, "There are two manner of people in thy womb, and two nations shall spring out of thy bowels, and the one nation shall be mightier than the other and the eldest shall be servant unto 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 to Jesse, "Are here all thy children?" And he said, "The youngest is yet behind. Behold, he keepeth the sheep." Then Samuel said unto Jesse, "Send and fetch him for we will not sit down, till he be come hither."
Genesis 25:23
And the LORD said unto her, "There are two manner of people in thy womb, and two nations shall spring out of thy bowels, and the one nation shall be mightier than the other and the eldest shall be servant unto the younger."