Al-Adab Al-Mufrad 1251
It is reported that al-Hasan said, "Are you not astonished by this man? (i.e. Malik ibn al-Mundhir) He went to some of the old people of Kaskar who had become Muslim and examined them and then commanded that they be circumcised although it was winter. I heard that some of them died. Greeks and Abyssinians became Muslim with the Messenger of Allah ﷺ and they were not examined at all."
حَدَّثَنَا مُحَمَّدٌ، قَالَ: أَخْبَرَنَا عَبْدُ اللهِ، قَالَ: أَخْبَرَنَا مُعْتَمِرٌ قَالَ: حَدَّثَنِي سَالِمُ بْنُ أَبِي الذَّيَّالِ، وَكَانَ صَاحِبَ حَدِيثٍ، قَالَ: سَمِعْتُ الْحَسَنَ يَقُولُ: أَمَا تَعْجَبُونَ لِهَذَا؟ يَعْنِي: مَالِكَ بْنَ الْمُنْذِرِ عَمَدَ إِلَى شُيُوخٍ مِنْ أَهْلِ كَسْكَرَ أَسْلَمُوا، فَفَتَّشَهُمْ فَأَمَرَ بِهِمْ فَخُتِنُوا، وَهَذَا الشِّتَاءُ، فَبَلَغَنِي أَنَّ بَعْضَهُمْ مَاتَ، وَلَقَدْ أَسْلَمَ مَعَ رَسُولِ اللهِ ﷺ الرُّومِيُّ وَالْحَبَشِيُّ فَمَا فُتِّشُوا عَنْ شَيْءٍ.