The Book of Faith (Kitab Al-Iman)
Muslim :: Book 1 : Hadith 13
It is narrated on the authority of Abu Ayyub that a man came to the Prophet (may peace be upon him) and said: Direct me to a deed which draws me near to Paradise and takes me away from the Fire (of Hell). Upon this he (the Holy Prophet) said: You worship Allah and never associate anything with Him, establish prayer, and pay Zakat, and do good to your kin. When he turned his back, the Messenger of Allah (may peace be upon him) remarked: If he adheres to what he has been ordered to do, he would enter Paradise.