It was narrated from Talhah bin 'Ubaidullah that:
a Bedouin came to the Messenger of Allah with unkempt hair and said: O Allah has enjoined upon me of Salah. He said: The five daily prayers, unless you do any more voluntarily. He said: Tell me what Allah has enjoined upon me voluntarily. He said: Tell me what Allah has enjoined upon me of fasting. He said: Fasting the month of Ramadan, unless you do any more voluntarily. He said: Tell me what Allah has enjoined upon me of Zakah. The Messenger of Allah told him of the laws of Islam, He said: By the One Who has honored you, I will not do anything voluntarily, and I will not do anything voluntarily, and I will not do less than that which Allah has enjoined upon, me: The Messenger of Allah said: He will succeed if he is sincere, or He will enter Paradise if he is sincere.