Umar's Disobedience
Position: Because Umar, the second Caliph, disobeyed Muhammad directly when the Prophet asked to write something to prevent Muslims from going astray, he cannot be considered reliable or rightly guided. Yet many things, such as the Islamic law of inheritance, are based on his ruling.
Sahih al-Bukhari 5669
Narrated Ibn `Abbas:
> When God's Messenger was on his death-bed and in the house there were some people among whom was `Umar bin Al-Khattab, the Prophet said, "Come, let me write for you a statement after which you will not go astray." `Umar said, "The Prophet is seriously ill and you have the Qur'an; so the Book of God is enough for us." The people present in the house differed and quarreled. Some said "Go near so that the Prophet may write for you a statement after which you will not go astray," while the others said as `Umar said. When they caused a hue and cry before the Prophet, God's Messenger said, "Go away!" Narrated 'Ubaidullah: Ibn `Abbas used to say, "It was very unfortunate that God's Messenger was prevented from writing that statement for them because of their disagreement and noise."
How can this man be considered "rightly guided?" It is clear from this Hadith, if it can be trusted, that he was not.