Sahih Bukhari
Interpretation of Dreams
Volume: 009 / Book Number: 087 / Hadith Number: 122
Narrated Abu Huraira:
I heard the Prophet saying, "Whoever sees me in a dream will see me in his wakefulness, and Satan cannot imitate me in shape." Abu 'Abdullah said, "Ibn Sirin said, 'Only if he sees the Prophet in his (real) shape.'"