Under the same heading falls their dispute about a Christian who declares tadbīr over a Christian slave of his, after which the slave accepts Islam before the master’s death.

Al-Shāfiʿī rules that the slave must be sold immediately upon his conversion and that the tadbīr thereby lapses.

Mālik holds that the slave is to be kept apart from his master, that the master is compelled to pay over the slave’s price, and that the slave himself is not to be sold until the master’s situation is resolved. If the master dies, the mudabbir is set free—unless the master’s debts exhaust his estate.

The Kufan jurists say: when the mudabbir of a Christian becomes Muslim, his value is assessed and the slave must work to pay that amount.

Furthermore, in Mālik’s view, a mudabbir appointed while the master was in good health takes precedence over one appointed during the master’s final illness whenever the bequeathable one-third of the estate is insufficient to cover both.