That 'Abdullah said: "On the Day of Badr when the captives were gathered, the Messenger of Allah ﷺ said: 'What do you (people) say about these captives?'" Then he mentioned the story in the lengthy Hadith.  

لَمَّا كَانَ يَوْمُ بَدْرٍ وَجِيءَ بِالأُسَارَى قَالَ رَسُولُ اللَّهِ ﷺ مَا تَقُولُونَ فِي هَؤُلاَءِ الأُسَارَى فَذَكَرَ قِصَّةً فِي هَذَا الْحَدِيثِ طَوِيلَةً