It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) ruled concerning debt that "it comes before the bequest."
The people of hadith do not regard this as established, because al-Harith al-A'war alone narrates it from Ali (may Allah be pleased with him), and al-Harith's report is not used as proof since the hadith masters have criticised him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوصايا / 12561