1 Samuel 17:12-15

17:12 Now David was the son of this Ephrathite named Jesse from Bethlehem in Judah. He had eight sons, and in Saul’s days he was old and well advanced in years. 17:13 Jesse’s three oldest sons had followed Saul to war. The names of the three sons who went to war were Eliab, his firstborn, Abinadab, the second oldest, and Shammah, the third oldest. 17:14 Now David was the youngest. While the three oldest sons followed Saul, 17:15 David was going back and forth from Saul in order to care for his father’s sheep in Bethlehem.

1 Samuel 17:28

17:28 When David’s oldest brother Eliab heard him speaking to the men, he became angry with David and said, “Why have you come down here? To whom did you entrust those few sheep in the desert? I am familiar with your pride and deceit! You have come down here to watch the battle!”