1 Samuel 17:12-16

Now David was the son of an Ephrathite named Jesse, who was from Bethlehem in Judah. Jesse had eight sons, and in Saul’s time he was very old.  Jesse’s three oldest sons had followed Saul to the war: The firstborn was Eliab; the second, Abinadab; and the third, Shammah.  David was the youngest. The three oldest followed Saul, but David went back and forth from Saul to tend his father’s sheep at Bethlehem.

 For forty days the Philistine came forward every morning and evening and took his stand.