Sahih Muslim Book 1, Hadith Number 334.

Chapter : The meaning of the words of Allah: “He saw Him in another descent” (Al-Qur’an 2, liii. 13).Did the Apostle (may peace be upon him) see his Lord on the night of his journey (to Heaven) ?.

It is narrated on the authority of Ibn ‘Abbas that he (the Holy Prophet) saw (Allah) with, his heart.