Ibn Tawus narrates from his father (may Allah have mercy on them both) that when a man bequeaths something that was obligatory upon him, such as Hajj, the expiation for an oath or the expiation for zihar, it is to be taken from all his wealth.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوصايا / 12600