All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Al-Ghazali mentioned a hadith in Al-Ihya on the authority of Abu Dharr that Abu Bakr said, “O Messenger of Allah, is there any kind of jihad other than fighting the polytheists?” He said, “Yes, O Abu Bakr. Allah the Exalted has mujaahideen (fighters in the cause of Allah) on earth who are better than the martyrs.” Then he mentioned the hadith in which he said, “They are those who enjoin good and forbid evil, those who love for the sake of Allah and hate for the sake of Allah.” Then he said, “By Him in Whose Hand my soul is! A slave among them is to be in a chamber above the chambers, above the chambers of the martyrs, for a chamber of them has three hundred thousand doors, among them are sapphire and green emeralds, on each door there is light, and a man among them is to marry three hundred thousand houris, who restrain their glances (desire none except their husbands), with wide and beautiful eyes. Whenever he looks at one of them, she says to him. “Do you remember on such-and-such a day that you enjoined good and forbade evil? Whenever he looks at one of them, she mentions to him a situation in which he enjoined good and forbade evil.” [End of quote].
It was also mentioned by Ibn al-Nahhas al-Dimashqi in Tanbeeh al-Ghafileen 'an 'A'maal al Jahileen wa Tahdheer as-Salikeen min Af'aal al-Jaheleen.
Al-‘Iraqi said concerning this hadeeth in Takhreej Ahadeeth al-Ihya: “I could not find any source for it and it is a Munkar (Odd) hadith”.
Allah knows best.