Saul saves Jabesh-gilead from Nash the Ammonite
Nahash the Ammonite went up and besieged Jabesh-gilead. When the people of Jabesh sought to cut a treaty, Nahash would only accept if he could gouge out all their right eyes and thus disgrace Israel. Upon elders' request, he gave them 7 days. (1 Samuel 11:1-3)
Saul and 300,000 people of Israel and 30,000 people of Judah in three companies struck down the Ammonites, scattering the survivors. (1 Samuel 11:5-11)
Jabesh-gilead are loyal to Saul
When the Philistines found the bodies of Saul and his sons, they cut off Saul's head, stripped his armor, sent messengers throughout Philistia to carry news to the house of their idols and the people, and put his armor in the temple of Ashtaroth and fastened his body to the wall of Beth-shan. The people of Jabesh-gilead heard this, went all night to take the body of Saul and his sons and came to Jabesh to burn them there. Their bones were buried under the tamarisk tree in Jabesh, and they fasted 7 days. (1 Samuel 31)
When David was in the towns of Hebron in Judah, he was told the men of Jabesh-gilead were the ones to bury Saul, so David sent messengers to them to say, "May you be blessed by the LORD, because you showed this loyalty to Saul your lord and buried him. Now may the LORD show steadfast love and faithfulness to you. And I will do good to you because you have done this thing. Now therefore let your hands be strong, and be valiant, for Saul your lord is dead, and the house of Judah has anointed me king over them." (2 Samuel 2:3-7)
David retrieves Saul's and Jonathan's bones for a proper interment
During a 3-year famine, King David sought the LORD and learned of the bloodguilt of Saul's house against the Gibeonites. They asked for 7 of Saul's sons to hang in Gibeah of Saul, but David spared Mephibosheth because of the oath of the Lord that was between them, between David and Jonathan the son of Saul.
Rizpah's unrelenting care for her sons' hanged bodies motivated David to gather Saul and Jonathan's bones from Jabesh-gilead and his sons' bones from Gibeah of Saul and bury them in the land of Benjamin in Zela in the tomb of Kish.