Bismillah Walhamdulillah Was Salaatu Was Salaam ‘ala Rasulillah Narrated Talha bin ‘Ubaidullah (Radi-Allahu ‘anhu):
A man came to Allah’s Apostle (Sallallahu ‘Alaihi Wa Sallam) asking him about Islam, Allah’s Apostle said, “You have to offer five compulsory prayers in a day and a night (24 hours).” The man asked, “Is there any more compulsory prayers for me?” Allah’s Apostle (Sallallahu ‘Alaihi Wa Sallam) said, “No, unless you like to offer Nawafil (i.e. optional prayers).” Allah’s Apostle then added, “You have to observe fasts during the month of Ramadan.” The man said, “Am I to fast any other days?’ Allah’s Apostle (Sallallahu ‘Alaihi Wa Sallam) said, “No, unless you wish to observe the optional fast voluntarily.”
Then Allah’s Apostle told him about the compulsory Zakat.
The man asked, “Do I have to give anything besides?”
Allah’s Apostle (Sallallahu ‘Alaihi Wa Sallam) said, “No, unless you wish to give in charity voluntarily.” So, the man departed saying, “By Allah I will neither do more nor less than that.” Allah’s Apostle (Sallallahu Alaihi Wa Sallam) said, “If he has said the truth he will be successful.”
Bukhari Vol. 3 : No. 843