It is not permissible to celebrate Isra’ (Night Journey) and Mi’raj (Ascension to Heaven) on the 27th night of Rajab, based on evidence from the Book, the Sunnah, Istis-hab (presumption of continuity) and reason. The following article helps to explain why, and is an excerpt from a Fatwa by Shaykh Muhamad Ibrahim Aali Shaykh – www.alifta.com