He reported God’s Messenger as saying, “A sister’s son has blood- relationship to her family.” (Bukhari and Muslim.)

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «ابْنُ أُخْتِ الْقَوْمِ مِنْهُم».