Is it permissible for a Muslim to sell a slave to an infidel?

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Ahmad ibn Hanbal prohibits the sale of any Muslim slave to an infidel, regardless of whether the slave is Muslim or not. This view is attributed to Al-Hasan. Ahmad states that people of Dhimma (non-Muslim citizens under Muslim rule) are not permitted to purchase anything from the spoils captured by Muslims. This is based on a decree written by Umar ibn Al-Khattab forbidding the governors of the provinces from allowing such transactions. The argument supporting this prohibition is that selling the slave to an infidel causes the loss of the apparent existence of Islam associated with that slave being in Muslim ownership. This differs from the initial ownership by an infidel, where no such benefit (pertaining to the display of Islam) is established, and continuation differs from origination due to stronger implication.