So why would Imam Ghazaali say: "the 27th of rajab as it is the night of the prophets ascension to heaven. The prophet said about this night of mercy (note, he calls it a night of mercy) : If a man does good deeds on this night he gets the rewards of one hundred years....." for Imam Ghazzali to mention it among 15 special nights, there must be some evidence for it.