Mukhtasar Bukhari

Ameer-ul-Mu'mineen Umar bin Khattab (may Allah be pleased with him) says that: These six people with whom the Messenger of Allah (peace and blessings of Allah be upon him) remained pleased until his death (no one is more deserving of the caliphate than them, so choose a caliph from among them). Then he mentioned the names of these six people: Uthman, Ali, Talha, Zubair, Abdur Rahman bin Awf, and Sa'd bin Abi Waqqas (may Allah be pleased with them).