Hadith 1423B1

قَالَ مَالِك : الْأَمْرُ الْمُجْتَمَعُ عَلَيْهِ عِنْدَنَا، أَنَّ شَهَادَةَ الصِّبْيَانِ تَجُوزُ فِيمَا بَيْنَهُمْ مِنَ الْجِرَاحِ، وَلَا تَجُوزُ عَلَى غَيْرِهِمْ، وَإِنَّمَا تَجُوزُ شَهَادَتُهُمْ فِيمَا بَيْنَهُمْ مِنَ الْجِرَاحِ وَحْدَهَا لَا تَجُوزُ فِي غَيْرِ ذَلِكَ إِذَا كَانَ ذَلِكَ قَبْلَ أَنْ يَتَفَرَّقُوا أَوْ يُخَبَّبُوا أَوْ يُعَلَّمُوا، فَإِنِ افْتَرَقُوا فَلَا شَهَادَةَ لَهُمْ إِلَّا أَنْ يَكُونُوا قَدْ أَشْهَدُوا الْعُدُولَ عَلَى شَهَادَتِهِمْ قَبْلَ أَنْ يَفْتَرِقُوا
Imam Malik, may Allah have mercy on him, said that if boys fight and injure each other, their testimony is valid, but the testimony of boys is not valid in other cases and lawsuits. This is also valid only if, after fighting, they did not separate but remained together. If they went their separate ways, then their testimony is not valid, unless they made just people witnesses to their testimony.
Hadith Reference موطا امام مالك رواية يحييٰ / كتاب الأقضية / 1423B1
Hadith Takhrij «فواد عبدالباقي نمبر: 36 - كِتَابُ الْأَقْضِيَةِ-ح: 9»