Salih ibn Hayy reported that a man said to 'Amir ash-Shu'bi, "Abu 'Amr! We say that when a man frees his umm walad and then marries her, he is like the one who rides his camel." 'Amir said, "Abu Burda related to me from his father that the Messenger of Allah ﷺ said to them:
'Three have a double reward: one of the People of the Book who believes in his Prophet and then believes in Muhammad has two rewards. When a slave carries out the due of Allah and the due of his master, he has a double reward. And (the third is) a man who has a slavegirl with whom he has intercourse and teaches her well and instructs her well and then sets her free and marries her. He has two rewards.'"

حَدَّثَنَا مُحَمَّدُ بْنُ سَلاَمٍ، قَالَ: أَخْبَرَنَا الْمُحَارِبِيُّ، قَالَ: حَدَّثَنَا صَالِحُ بْنُ حَيٍّ قَالَ: قَالَ رَجُلٌ لِعَامِرٍ الشَّعْبِيِّ: يَا أَبَا عَمْرٍو، إِنَّا نَتَحَدَّثُ عِنْدَنَا أَنَّ الرَّجُلَ إِذَا أَعْتَقَ أُمَّ وَلَدِهِ ثُمَّ تَزَوَّجَهَا كَانَ كَالرَّاكِبِ بَدَنَتَهُ، فَقَالَ عَامِرٌ: حَدَّثَنِي أَبُو بُرْدَةَ، عَنْ أَبِيهِ قَالَ: قَالَ لَهُمْ رَسُولُ اللهِ ﷺ: ثَلاَثَةٌ لَهُمْ أَجْرَانِ: رَجُلٌ مِنْ أَهْلِ الْكِتَابِ آمَنَ بِنَبِيِّهِ، وَآمَنَ بِمُحَمَّدٍ ﷺ فَلَهُ أَجْرَانِ. وَالْعَبْدُ الْمَمْلُوكُ إِذَا أَدَّى حَقَّ اللهِ وَحَقَّ مَوَالِيهِ. وَرَجُلٌ كَانَتْ عِنْدَهُ أَمَةٌ يَطَأهَا، فَأَدَّبَهَا فَأَحْسَنَ تَأْدِيبَهَا، وَعَلَّمَهَا فَأَحْسَنَ تَعْلِيمَهَا، ثُمَّ أَعْتَقَهَا فَتَزَوَّجَهَا، فَلَهُ أَجْرَانِ قَالَ عَامِرٌ: أَعْطَيْنَاكَهَا بِغَيْرِ شَيْءٍ، وَقَدْ كَانَ يَرْكَبُ فِيمَا دُونَهَا إِلَى الْمَدِينَةِ.