Al-Qasim bin Rabi'ah bin Qanif said: I recited before Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) until I reached this verse: "And if a man or a woman is inherited as kalalah (leaving neither parent nor child), and he has a brother" [Surah al-Nisa: 12]. Sayyiduna Sa'd (may Allah be pleased with him) said: A brother from the mother's side.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12262