Someone asked me why do we single out 27th Rajab as the Night of Ascension and not the 17th/27th of Rabiul Awwal. Can anyone advise?
Does it not depend on how weak it actually is. Like the weakness of someone being accused of lying or extreme blunders is more than one who had a poor memory. I believe Shaykh Asrār mentioned something on this that as long as there is no critical weakness it is fine to use in faḍāʿīl and targhib wa-tarhib
There are hadith on the merits of fasting and praying on 27th Rajab. Although they are weak, because they are on merits, they are accepted and acted upon. Sunni ulama of Syria, Yemen, Madinah, Morocco and Egypt perform these practices. And, of course, Sunnis of the subcontinent certainly do so. There is ijma'a of scholars that weak hadith are allowed to be acted upon in the chapter of merits. #Alahazrat cites various references beginning at 10:647 in his fatāwā.