The following is from page 289 of Islam in the School of Madina:
Sayyidi Abd ar-Rahman ath-Tha’alibi – may Allah benefit us by him – has commented on the words of Allah “and let him not associate anyone in the worship of his Lord” (Quran 18:110) saying: “take note: it has been narrated to us in Sahih Muslim from Jabir, may Allah, exalted is He, be pleased with him, that he said: ‘I have heard the prophet ﷺ say: ‘surely there is an hour in the night – no Muslim man succeeds in witnessing it and in asking Allah for good but that he will be granted it – and this (applies) every night.’ ‘ If you want to know which is this hour then recite the following words of the Most High before you sleep: ‘those who have iman and do right actions will have the Gardens of Firdaws as hospitality… (Quran 18:107)’ to the end of the surah. (If you do this) you will wake up at this hour insha’Allah, exalted is He, by His overflowing generosity.
By whatever means you wake up, however, then make du’a for me and for yourself. This is one of the things that Allah glorious and exalted is He, has revealed to me and so take benefit from it. I have only written it down after making istikhara. Take care that you do not make a du’a against a Muslim during this (hour) – even if he is a tyrant. If you act contrary to my (instructions) then Allah will be your Reckoner and I will be your adversary in front of Him. I desire of you that you let me share in your du’a – given that I have accorded you this great benefit – and that I act as your Shaykh in it. Surely the Qur’an contains secrets which Allah reveals to those of His awliya He wishes – may Allah, exalted is He, make us of them by His overflowing generosity.” Here ends his words, may Allah be pleased with him and benefit us by them. I say: “and I also desire of you that you permit me to share in your du’a.”