sahih Muslim Sharif, Book 1, Chapter 78, hadith number 337 (Abdul Hamid Sidiqqi Translation), which is:

It is narrated on the authority of Masruq that he said: I was resting at (the house of) 'A'isha that she said: O Abu 'A'isha (kunya of Masruq), there are three things, and he who affirmed even one of them fabricated the greatest lie against Allah. I asked that they were. She said: He who presumed that Muhammad (may peace be upon him) saw his Lord fabricated the greatest lie against Allah. I was reclining but then sat up and said: Mother of the Faithful, wait a bit and do not be in a haste. Has not Allah (Mighty and Majestic) said: "And truly he saw him on the clear horizon" (al-Qur'an, lxxxi. 23) and "he saw Him in another descent" (al-Qur'an, iiii. 13)? She said: I am the first of this Ummah who asked the Messenger of Allah (may peace be upon him) about it, and he said: Verily he is Gabriel. I have never seen him in his original form in which he was created except on those two occasions (to which these verses refer); I saw him descending from the heaven and filling (the space) from the sky to the earth with the greatness of his bodily structure. She said: Have you not heard Allah saying. "Eyes comprehend Him not, but He comprehends (all) vision. and He is Subtle, and All-Aware" (al-Qur'an, v. 104)? (She, i.e. 'A'isha, further said): Have you not heard that, verily, Allah says: "And it is not vouchsafed to a human being that Allah should speak unto him otherwise than by revelation, or from behind a veil, or that He sendeth a messenger (angel), so that he revealth whatsoever He wills. Verily He is Exalted. Wise" (al. Qur'an, xii. 51)She said: He who presumes that the Messenger of Allah (may peace be upon him) concealed anything, from the Book, of Allah fabricates the greatest lie against Allah. Allah says: "O Messenger ! deliver that which has been revealed to thee from thy Lord, and if thou do (it) not, thou hast not delivered His message" (al-Qur'an, v. 67). She said: He who presumes that he would inform about what was going to happen tomorrow fabricates the greatest lie against Allah. And Allah says "Say thou (Muhammad): None in the heavens and the earth knoweth the unseen save Allah" (al-Qur'an, xxvii 65).