Vowing to grant all or some of the property to a son

A: It is impermissible to vow to give all one's money to a son or a wife with the intention of depriving other legal heirs from inheritance. It is also impermissible to fulfill this vow, for the Hadith narrated by `Aishah (may Allah be pleased with her) who reported Allah's Messenger (peace be upon him) as stating, Whoever vows to obey Allah should obey Him, and whoever vows to disobey Allah should not disobey Him. Related by the five Hadith Compilers (Al-Bukhari, Abu Dawud, Al-Tirmidhi, Al-Nasa', and Ibn Majah) except Muslim. Thus whoever does this, should offer a Kaffarah (expiation) of oath, for what was narrated by `Aishah (may Allah be pleased with her) from the Prophet (peace be upon him), No vow is to be fulfilled in disobedience, and the expiation for it is the same as that for an oath. Related by Imam Ahmad and the Four Compilers of Hadith (Imams Abu Dawud, Al-Tirmidhi, Al-Nasa'i and Ibn Majah). However, the Prophet (peace be upon him) forbade that a man single out some of his sons with anything in preference to other sons, (Part No. 23; Page No. 240) as mentioned in the Hadith related by Al-Bukhari and Muslim on the authority of Al-Nu`man ibn Bashir (may Allah be pleased with him) who said, My father granted me some of his property. My mother said: I shall not agree (to this act) until you call Allah's Messenger (peace be upon him) to witness it. My father went to Allah's Messenger (peace be upon him) in order to make him witness the donation given to me. Allah's Messenger (peace be upon him) said to him, "Have you done the same with all your sons?" He said, "No." Thereupon he (peace be upon him) said, "Fear Allah, and treat your children equally." He (Al-Nu`man) said, "My father returned and took back the gift." The Prophet also said, Allah has appointed for everyone who has a right what is due to them, and no bequest is to be made to an heir." May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.