Sahih Muslim Book 1, Hadith Number 54.

Chapter : He relished the flavour of Iman who was pleased with Allah as his Lord.

It is narrated on the authority of ‘Abbas b. ‘Abdul-Muttalib that he heard the Messenger of Allah saying: He relished the flavour of faith (Iman) who became the book of faith pleased with Allah as Lord, with al-Islam as the code of life and with Muhammad as the Messenger (of Allah).