The Ruling on Contracting Marriage with One's Maternal Uncle's Daughter After Breastfeeding by His Wife

Question:
Perhaps this is the last question. The questioner writes that he was breastfed by his maternal uncle’s wife five times or more, and he contracted a marriage with his maternal uncle’s daughter and prepared for it, meaning that several years have passed since he contracted the marriage. Is this contract valid, and is the marriage to be consummated?

Answer:
No, as long as he was breastfed by his maternal uncle’s wife—whether it was his wife or his maternal uncle’s daughter—as long as he was breastfed by his maternal uncle’s wife five times within the first two years, it is not permissible to contract a marriage with his maternal uncle’s daughter, whether it is the one who breastfed him, the one before her, or any of his maternal uncle’s daughters. All of his maternal uncle’s daughters are his sisters, whether from the wet nurse or from another wife. It is not permissible for him to contract a marriage with any of them. If he has already contracted the marriage, the contract is invalid, and he must return the money he gave to his maternal uncle, or the gold he left behind; that is his right. The important point is that the contract is invalid.