The Messenger of Allah said: "There is no vow for the son of Adam over what he has no control, and there is no emancipating he can do for one whom he does not own, and there is no divorce for him regarding that which he has no control over."  

قَالَ رَسُولُ اللَّهِ ﷺ لاَ نَذْرَ لاِبْنِ آدَمَ فِيمَا لاَ يَمْلِكُ وَلاَ عِتْقَ لَهُ فِيمَا لاَ يَمْلِكُ وَلاَ طَلاَقَ لَهُ فِيمَا لاَ يَمْلِكُ قَالَ وَفِي الْبَابِ عَنْ عَلِيٍّ وَمُعَاذِ بْنِ جَبَلٍ وَجَابِرٍ وَابْنِ عَبَّاسٍ وَعَائِشَةَ