A weapon.
Saul's spears
Saul hurls spears at David
Saul was angry at David and, when the harmful spirit that tormented him returned, he raved while David played the lyre. Saul had his spear in his hand premeditatively and ended up hurling it at David twice. (1 Samuel 18)
When a war came and another victory for David, a harmful spirit from the LORD came upon Saul, as he sat in his house with his spear in his hand. As David played the lyre, Saul tried to pin David to no success. (1 Samuel 19)
Saul hurls a spear at Jonathan
David failed to come to Saul's table one day, and Jonathan lied to cover for him. Saul became angry, and Jonathan asked why David deserved death. Jonathan asked what David had done to deserve death. Saul hurled his spear at him, so Jonathan rose from the table without eating and left. (1 Samuel 20)
Saul hunts down David with his spear in hand
When Saul heard David was discovered with 400 men. Saul was sitting at Gibeah under the tamarisk tree with his spear, and he asked his servants if the son of Jesse would give them vineyards, make them commanders, that they would conspired against him. Doeg the Edomite told him he had seen David coming to Nob. (1 Samuel 22:6-19)
Hunt continues, and David steals his spear
The Ziphites told Saul at Gibeah that David hid on the hill of Hachilah. Saul pursued him in the wilderness of Ziph with Abner the son of Ner and 3000 men and camped on the hill of Hachilah beside the road on the east of Jeshimon. He slept with his spear stuck in the ground at his head and his commander and army around him. David came in the night with Abishai the son of Zeruiah and took his spear and jar of water. The LORD sent a deep sleep, so no one noticed.
From a great space, David called to Abner that he had not protected the LORD's anointed and deserved death. His spear and jar of water are missing. Saul recognized David, and David asked him that if he was stirred by the LORD that the LORD may accept an offering, but if he was stirred by men, that they may be cursed. They had driven David out so he had no share in the heritage of the LORD, telling him to serve other gods. Saul claimed to be in sin and asked David to return in peace. David offered his spear back to one of Saul's young men and asked the LORD to see his own life as precious like how he had viewed Saul's. Saul blessed him, and David went his way, and Saul returned to his place for now. (1 Samuel 26)