Mansur (may Allah have mercy on him) said: Some people during the time of Hajjaj were hiding in an upper room on the right side of the mosque; they would perform the obligatory prayer with the Imam and follow him. So I asked Ibrahim (may Allah have mercy on him) about this, and he said: Their prayer is valid.
Hadith Referenceسنن سعید بن منصور / كتاب التفسير / 1074
Hadith Gradingمحدثین:سنده صحيح.
Hadith Takhrij«أخرجه سعيد بن منصور فى (سننه) برقم: 1074، وابن أبى شيبة فى (مصنفه) برقم: 6218»