Is the manumission of a male slave superior to the manumission of a female slave?

Primary text

The manumission of a male slave is superior to the manumission of a female slave. This is supported by the narration of Ka'b ibn Umaimah al-Bahzi, who heard the Messenger of God, peace be upon him, state: 'Any man who frees a Muslim male shall have every bone of his own body recompensed by a bone of that slave's body freed from the Fire. Any man who frees two Muslim females shall have every bone of their bodies recompensed by a bone of his own body freed from the Fire. And any Muslim woman who frees a Muslim female shall have every bone of her own body recompensed by a bone of that slave's body freed from the Fire.'