Al-Hakam bin Mas'ud al-Thaqafi said: I was present with Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) when he made the full brothers share with the maternal brothers in the third. A man said to him: Last year you judged this differently. Sayyiduna Umar (may Allah be pleased with him) asked: How did I judge? He said: You gave it to the maternal brothers and gave nothing to the full brothers. Sayyiduna Umar (may Allah be pleased with him) said: That was according to how we judged then, and this is according to how we judge now.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12467