Musannaf Ibn Abi Shaybah

Hasan and Ibrahim say that if a slave marries without his master's permission, and then the master grants him permission, it is permissible.

Hasan says that if a slave marries without his master's permission, then the master grants him permission, it is permissible.

Hazrat Saeed bin Musayyib and Hasan say that if a slave marries without his master's permission, then the master may allow it if he wishes, or forbid it if he wishes.

Hazrat Hakam says that if the master keeps the slave's marriage intact, it will remain intact. Hazrat Hammad says that upon receiving permission, he will perform the marriage again.