Sunan an-Nasa'i, Volume 5, Book 44, Hadith 4660 (DarusSalam) ⓘ

It was narrated that 'Aishah said: "Barirah came to me and said: 'O 'Sishah, I have drawn up a contract of manumission with my master, (to buy my freedom) in return for nine Uwqiyah, one Uwqiyah to be paid each year; help me,' she had not yet paid anything toward her contract of manumission.' 'Aishah, who liked her and wanted to help her, said: 'Go back to your masters and if they agree to let me pay the whole sum and that your loyalty will be to me, I will do it.' So Barirah went to her masters and suggested that to them, but they refused and said: 'if she wants to seek reward (with Allah) by freeing you, let her do so, but (you loyalty) will be to us, 'Aishah told the Messenger of Allah about that and he said: 'Do not let that stop you. Buy her and set her free, and loyalty belongs to the one who sets the slave free.; so she did that, then the Messenger of Allah stood up before the people, praised and glorified Allah, then said: 'What is the matter with people who stipulate conditions that are not in the Book of Allah? Whoever stipulates conditions that are not in even if there are a hundred conditions? The decree of Allah takes priority, and the conditions of Allah binding. And loyalty belongs to the one who sets the slaves free.'

أَخْبَرَنَا يُونُسُ بْنُ عَبْدِ الأَعْلَى، قَالَ أَنْبَأَنَا ابْنُ وَهْبٍ، قَالَ أَخْبَرَنِي رِجَالٌ، مِنْ أَهْلِ الْعِلْمِ مِنْهُمْ يُونُسُ وَاللَّيْثُ أَنَّ ابْنَ شِهَابٍ أَخْبَرَهُمْ عَنْ عُرْوَةَ عَنْ عَائِشَةَ أَنَّهَا قَالَتْ جَاءَتْ بَرِيرَةُ إِلَىَّ فَقَالَتْ يَا عَائِشَةُ إِنِّي كَاتَبْتُ أَهْلِي عَلَى تِسْعِ أَوَاقٍ فِي كُلِّ عَامٍ أُوقِيَّةٌ فَأَعِينِينِي ‏.‏ وَلَمْ تَكُنْ قَضَتْ مِنْ كِتَابَتِهَا شَيْئًا فَقَالَتْ لَهَا عَائِشَةُ وَنَفِسَتْ فِيهَا ارْجِعِي إِلَى أَهْلِكِ فَإِنْ أَحَبُّوا أَنْ أُعْطِيَهُمْ ذَلِكَ جَمِيعًا وَيَكُونَ وَلاَؤُكِ لِي فَعَلْتُ ‏.‏ فَذَهَبَتْ بَرِيرَةُ إِلَى أَهْلِهَا فَعَرَضَتْ ذَلِكَ عَلَيْهِمْ فَأَبَوْا وَقَالُوا إِنْ شَاءَتْ أَنْ تَحْتَسِبَ عَلَيْكِ فَلْتَفْعَلْ وَيَكُونَ ذَلِكَ لَنَا ‏.‏ فَذَكَرَتْ ذَلِكَ عَائِشَةُ لِرَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏"‏ لاَ يَمْنَعُكِ ذَلِكَ مِنْهَا ابْتَاعِي وَأَعْتِقِي فَإِنَّ الْوَلاَءَ لِمَنْ أَعْتَقَ ‏"‏ ‏.‏ فَفَعَلَتْ وَقَامَ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي النَّاسِ فَحَمِدَ اللَّهَ تَعَالَى ثُمَّ قَالَ ‏"‏ أَمَّا بَعْدُ فَمَا بَالُ النَّاسِ يَشْتَرِطُونَ شُرُوطًا لَيْسَتْ فِي كِتَابِ اللَّهِ مَنِ اشْتَرَطَ شَرْطًا لَيْسَ فِي كِتَابِ اللَّهِ فَهُوَ بَاطِلٌ وَإِنْ كَانَ مِائَةَ شَرْطٍ قَضَاءُ اللَّهِ أَحَقُّ وَشَرْطُ اللَّهِ أَوْثَقُ وَإِنَّمَا الْوَلاَءُ لِمَنْ أَعْتَقَ ‏"‏ ‏.‏