It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) "ruled that debt comes before the bequest," while you recite: "after any bequest that is made or a debt" [Surah al-Nisa: 12]. And the children of the same mother (and father) inherit to the exclusion of the paternal half-siblings: full brothers and sisters inherit to the exclusion of the paternal half-brothers and half-sisters.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12375