I said to Ka'b bin Murrah, tell us a Hadith from the Messenger of Allah ﷺ, but be careful. He said: I heard the Messenger of Allah ﷺ say: “Whoever frees a Muslim man, he will be his ransom from the Fire; each of his bones will suffice (as a ransom) for each of his bones. Whoever frees two Muslim women, they will be his ransom from the Fire; each of their two bones will suffice (as a ransom) for each of his bones.” (Using translation from Ibn Mājah 2522)
حَدِّثْنَا عَنْ رَسُولِ اللهِ ﷺ وَاحْذَرْ قَالَ سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ «مَنْ أَعْتَقَ امْرَأً مُسْلِمًا كَانَ فِكَاكَهُ مِنَ النَّارِ يُجْزِئُ كُلُّ عَظْمٍ مَكَانَ عَظْمٍ مِنْهُ وَمَنْ أَعْتَقَ امْرَأَتَيْنِ مُسْلِمَتَيْنِ كَانَتَا فِكَاكَهُ مِنَ النَّارِ يَجْزِئُ مَكَانَ كُلِّ عَظْمَيْنِ مِنْهُمَا عَظْمٌ مِنْهُ»