Sunan an-Nasa'i, Volume 5, Book 45, Hadith 4843 (DarusSalam) ⓘ

It was narrated from Tariq and Muharibi that a manh said: "O Messenger of Allah, these are Banu Tha'labah who killed so and so during the Jahiliyyah: avenger us! He raised his arms until the whiteness of his armpits could be seen and said: "No mother's sin can affect her child," twice. (Shaih)

أَخْبَرَنَا يُوسُفُ بْنُ عِيسَى، قَالَ أَنْبَأَنَا الْفَضْلُ بْنُ مُوسَى، قَالَ أَنْبَأَنَا يَزِيدُ، - وَهُوَ ابْنُ زِيَادِ بْنِ أَبِي الْجَعْدِ - عَنْ جَامِعِ بْنِ شَدَّادٍ، عَنْ طَارِقٍ الْمُحَارِبِيِّ، أَنَّ رَجُلاً، قَالَ يَا رَسُولَ اللَّهِ هَؤُلاَءِ بَنُو ثَعْلَبَةَ الَّذِينَ قَتَلُوا فُلاَنًا فِي الْجَاهِلِيَّةِ ‏.‏ فَخُذْ لَنَا بِثَأْرِنَا ‏.‏ فَرَفَعَ يَدَيْهِ حَتَّى رَأَيْتُ بَيَاضَ إِبْطَيْهِ وَهُوَ يَقُولُ ‏ "‏ لاَ تَجْنِي أُمٌّ عَلَى وَلَدٍ ‏" ‏ ‏.‏ مَرَّتَيْنِ ‏.‏