Ideas about the Kingdom of the Heavens around us and the unity of believers in Christ within it
True repentance would have required high priest Eli to act to remove his sons Hophni and Phinehas from office. Hophni and Phinehas were using God and their offices as a magical charm and using others, as many in the Church do today. The people also learned to do these things from their example. Instead of removing them, Eli just nagged them, and he and all Israel paid the penalty.
When Jesus unfavorably compared the unrepentance of the Galilean towns where he had preached to the repentance Tyre, Sidon and Sodom would have shown to the same preaching. the repentance of which he spoke clearly included behavioral change.
Jesus contrasted the Jewish leaders, who refused to hear his words, with the Ninevites who repented at the preaching of Jonah and put away their bloodshed and violence.