Muhammad bin Muslim bin Tadras محمد بن مسلم بن تدرس أبو الزبير · The Book of Marriage

"The Messenger of Allah forbade taking a woman as a co-wife to her paternal aunt or her maternal aunt."

"The Messenger of Allah said to me: 'Have you got married?' I said: 'Yes.' He said: 'Have you got any Anmat?' I said: 'How can we afford Anmat?' He said: 'You will be able to.'"