Hadiths 7.35 to 7.37

7.35:
Narrated Aisha"
(regarding) the Verse: 'And if you fear that you shall not be
able to deal justly with the orphans...' ( 4.3) It is about
the orphan girl who is in the custody of a man who is her
guardian, and he intends to marry her because of her wealth,
but he treats her badly and does not manage her property
fairly and honestly. Such a man should marry women of his
liking other than her, two or three or four. 'Prohibited to
you (for marriage) are: ...your foster−mothers (who suckled
you).' ( 4.23) Marriage is prohibited between persons having a
foster suckling relationship corresponding to a blood
relationship which renders marriage unlawful.

7.36:
Narrated `Aisha:
(the wife of the Prophet) that while Allah's Apostle was with
her, she heard a voice of a man asking permission to enter the
house of Hafsa. `Aisha added: I said, "O Allah's Apostle! This
man is asking permission to enter your house." The Prophet
said, "I think he is so−and−so," naming the foster−uncle of
Hafsa. `Aisha said, "If so−and−so," naming her foster uncle,
"were living, could he enter upon me?" The Prophet said, "Yes,
for foster suckling relations make all those things unlawful
which are unlawful through corresponding birth (blood)
relations."

7.37:
Narrated Ibn `Abbas: It was said to the Prophet, "Won't you
marry the daughter of Hamza?" He said, "She is my foster niece
(brother's daughter). "