Sayyiduna Ibn Umar (may Allah be pleased with them both) said: "When the Messenger of Allah (peace and blessings be upon him) passed away, the Muslims looked to the best among them and made him their caliph, and he was Abu Bakr. Then when Abu Bakr passed away, the people looked to the best of the Muslims and made him caliph, and he was Umar. Then when he died, or was martyred, the Muslims looked to the best among them and made him caliph, and he was Uthman. If you kill him, then bring someone better than him; by Allah, I do not think you will be able to do so."
Imam al-Tabarani (may Allah have mercy on him) said: "Al-Qasim, from whom Qurrah bin Khalid narrated this hadith, is Abu Nahik of Basrah, who is Ibn Muhammad."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13175