Sahih Muslim Book 1, Hadith Number 11.

Chapter : Concerning Iman by which a person would enter Heaven.

It is narrated on the authority of Abu Ayyub Ansari that once during the journey of the Holy Prophet (may peace of Allah be upon him) a bedouin appeared before him and caught hold of the nose-string of his she-camel and then said, Messenger of Allah (or Muhammad), inform me about that which takes me near to Paradise and draws me away from the Fire (of Hell). He (the narrator) said: The Prophet (may peace be upon him) stopped for a while and cast a glance upon his companions and then said: He was afforded a good opportunity (or he had been guided well). He (the Holy Prophet) addressing the bedouin said: (Repeat) whatever you have uttered. He (the bedouin) repeated that. Upon this the Apostle (may peace be upon him) remarked: The deed which can draw you near to Paradise and take you away from Hell is, that you worship Allah and associate none with Him, and you establish prayer and pay Zakat, and do good to your kin. After having uttered these words, the Holy Prophet asked the bedouin to release the nose-string of his she-camel.