I heard the Messenger of Allah ﷺ say: If anyone emancipates a Muslim slave, that will be his ransom from Jahannam. (Using translation from Abū Dāʾūd 3966)  

حَدِّثْنَا حَدِيثًا سَمِعْتَهُ مِنْ رَسُولِ اللهِ ﷺ قَالَ سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «مَنْ أَعْتَقَ رَقَبَةً مُؤْمِنَةً كَانَتْ فِدَاءَهُ مِنَ النَّارِ عُضْوًا بِعُضْوٍ»  

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «مَنْ أَعْتَقَ رَقَبَةً مُؤْمِنَةً كَانَتْ فِكَاكَهُ مِنَ النَّارِ عُضْوًا بِعُضْوٍ»  

[Machine] Narrated from the Prophet of Allah, ﷺ , a complete and unforgetful hadith: "By the One in whose hand is the soul of Amr ibn Abasa, there is no man who sets free a believing slave except that for every limb of his, there is a limb of his saved from the Fire. I have surely heard this more than once."  

حَدِّثْنَا عَنْ نَبِيِّ اللهِ ﷺ حَدِيثًا لَيْسَ فِيهِ نَقْصٌ وَلَا نِسْيَانٌ قَالَ وَالَّذِي نَفْسُ عَمْرِو بْنِ عَبَسَةَ بِيَدِهِ «مَا مِنْ رَجُلٍ يُعْتِقُ رَقَبَةً مَسْلَمَةً إِلَّا فَدَتْ كُلَّ عُضْوٍ مِنْهُ عُضْوًا مِنْهُ مِنَ النَّارِ لَقَدْ سَمِعْتُهُ غَيْرَ مَرَّةٍ»  

I heard Messenger of Allah ﷺ as saying: He who emancipates a believing slave. Allah will set free from Fire his every limb for every limb of his (slave's), even his private parts for his. (Using translation from Muslim 1509c)   

سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «مَنْ أَعْتَقَ رَقَبَةً أَعْتَقَ اللهُ بِكُلِّ عُضْوٍ مِنْهَا عُضْوًا مِنْهُ مِنَ النَّارِ»