Sahih Bukhari Volume 002, Book 023, Hadith Number 480.
Narated By Abu Huraira : A Bedouin came to the Prophet and said, "Tell me of such a deed as will make me enter Paradise, if I do it." The Prophet (p.b.u.h) said, "Worship Allah, and worship none along with Him, offer the (five) prescribed compulsory prayers perfectly, pay the compulsory Zakat, and fast the month of Ramadan." The Bedouin said, "By Him, in Whose Hands my life is, I will not do more than this." When he (the Bedouin) left, the Prophet said, "Whoever likes to see a man of Paradise, then he may look at this man."