1 Samuel 17:12-17

12Now David was the son of the Ephrathite of Bethlehem in Judah, named Jesse, who had eight sons. Jesse was old in the days of Saul, advanced in years among men.

13His three older sons had followed Saul into battle. The names of his three sons who went to battle were Eliab, the firstborn; next, Abinadab; and third, Shammah.

14David was the youngest. Now the three oldest followed Saul,

15but David went back and forth from Saul to tend his father’s flock at Bethlehem.

16The Philistine [Goliath] came out morning and evening, and took his stand for forty days.

17Then Jesse said to David his son, “Take for your brothers an ephah of this roasted grain and these ten loaves of bread and run quickly to the camp to your brothers.