Khulafa' Arrasyidin

Who will give you a more pure form of understanding than the man who traveled miles and miles of desert with the Prophet to seek aid and hostage with him?

He is Abu Bakr

Who will give you a more pure form of understanding than the one hid between the sheets of the Ka'abah to spy on the Prophet while unconsciously accepting the word of God and finally bowing down to Allah 3aza wa jal when hearing surah Taha?

He is Umar Al Khattab

Who will give you a more pure form of understanding than the man whom when he passed by Muhammad (saw), the Prophet covered his legs (out of shyness) because of the greatness of this man's piety?

He is Uthman Ibn Affan

Who will give you a more pure form of understanding than the first boy who cried out to the Prophet and told him he believed that he indeed was the messenger of Allah while he was mocked and laughed at by his own people?

And he is Ali b Abi Talib