سنن النسائي

It was narrated that Abu Al-Hasan, the freed slave of Banu Nawfal, said: "Ibn 'Abbas was asked about a slave who divorced his wife twice, then they were set free; could he marry her? He said: 'Yes.' He said: 'From whom (did you hear that)?' He said: 'The Messenger of Allah (ﷺ) issued a Fatwa to that effect.'" (One of the narrators) 'Abdur-Razzaq said: "Ibn Al-Mubarak said to Ma'mar: 'Which Al-Hasan is this? He has taken on a heavy burden.'"