Surah 53. An-Najm, Ayah 11

Inasmuch as the Prophet was fully aware of the spiritual character of his experience, there was no conflict between his conscious mind and his intuitive perception (the "vision of the heart") of what is normally not perceptible.

"Heart" in Arabic includes the faculty of intelligence as well as the faculty of feeling. The impression conveyed was pure truth; there was no illusion in it.