Musannaf Ibn Abi Shaybah

Ibrahim (may Allah have mercy on him) said that if a man mistakenly marries a woman who is forbidden to him (mahram) and consummates the marriage, the woman will receive the full dowry (mahr).

Hasan (may Allah have mercy on him) said: Whatever dowry a woman receives, it will belong to her.

It is also narrated in the same way from Hazrat Hammad, may Allah have mercy on him.

Hazrat Sha’bi (may Allah have mercy on him) says that a woman will not receive a dowry, whether the man has consummated the marriage or not. Would a man give dowry to his sister or mother?

Ibrahim (may Allah have mercy on him) said that if a man unknowingly marries his foster sister and later comes to know about it, then this marriage will be invalid. If consummation took place, then due to making the private part lawful, the dowry will be obligatory, and if consummation did not take place, then separation will be effected between the two without any dowry.

Hazrat Hakam (may Allah have mercy on him) says that if a person unknowingly marries his real or foster sister and then consummates the marriage, she will be entitled to the dowry.

Hasan (may Allah have mercy on him) said: She will receive the full dowry.

Hazrat Hammad (may Allah have mercy on him) says that for every intercourse in which there is no prescribed punishment, the full dowry (mahr) is due.

Hazrat Tawus (may Allah have mercy on him) says that if a man unknowingly marries his foster sister and even has intercourse with her, then separation will be enforced between them, and the woman will not receive the full dowry, but only a part of it.