2 Samuel 21:1-3

And there was a famine in the days of David three years, year after year; and David inquired of Jehovah. And Jehovah said, It is for Saul, and for his house of blood, because he slew the Gibeonites. And the king called the Gibeonites, and spoke to them. (Now the Gibeonites were not of the children of Israel, but of the remainder of the Amorites; and the children of Israel had sworn to them; and Saul sought to smite them in his zeal for the children of Israel and Judah.) And David said to the Gibeonites, What shall I do for you? and with what shall I make atonement, that ye may bless the inheritance of Jehovah?