‘Amr ibn Shu‘ayb reported from his father that his grandfather said that the Messenger of Allah (may Allah’s peace and blessings be upon him) said: “The son of Adam cannot make a vow concerning what is not his; he cannot free a slave who is not his; and he cannot divorce a woman who is not his (wife).”
In this Hadīth, the Prophet (may Allah's peace and blessings be upon him) explains that one can handle only things that he owns, and that disposing of things that one does not own is void. This rule applies to the acts mentioned in the Hadīth as follows: 1. The vow: Making a vow concerning a thing that one does not own at the time of making the vow is void. Even if one comes to own that thing later, he neither has to fulfill his vow nor offer expiation. 2. Emancipation of a slave: One cannot free a salve who is not his, because emancipation in this case in objectless. 3. Divorce: It is void if made by a man concerning a woman who is not his wife, because the right of divorce belongs exclusively to the husband who has the right to intimacy, and also because the Prophet (may Allah's peace and blessings be upon him) said: “One cannot divorce a woman who is not his (wife)”.