The answer is: Saul killed the Gibeonites

2 Sam 21:1

In 2 Samuel 21, we enter the complex world of ancient Israel, where history, justice, and divine favor intersect. The famine during King David’s reign isn't just a mere geographical event; it's a response that highlights the intertwined destinies of the Israelites and the Gibeonites. Following Israel’s comprehensive conquest and settling of the Promised Land, the Gibeonites, a non-Israelite group, strategically sought peace with the Israelites in Joshua chapter 9. They even went so far as to deceive Israel into aligning with them!

Fast forward to King Saul, who, in his bid for nationalist pride, aggressively targeted the Gibeonites. This unprovoked violence led to consequences long into the future—showing us that bloodshed does not fade with the passing of time. David consults the traditions of justice instead of merely stacking his own personal agenda, which reflects a significant moral awareness he carried as a ruler.

This narrative evokes echoes of later biblical themes, such as God’s continual covenant with His people and His incomprehensible mercy, but also justice that must be upheld, lending insights into how we understand disputes and resolutions today. It's fascinating to note that many biblical events depict famines, which often biblically signify God’s judgment or, sometimes, a call to repentance and reflection. The famine during David's time is a profound reminder of how legacies of wrongdoing impact future generations—both in nations and our personal lives!