Narrated by Sayyiduna Abu Umamah Bahili (may Allah be pleased with him): He says, I heard the Messenger of Allah (peace and blessings be upon him) saying in the sermon during the year of the Farewell Pilgrimage: Allah Almighty has given every rightful person his due right, therefore, it is not permissible to make a bequest in favor of an heir. … al-Hadith