Is it permissible to marry the granddaughter of the woman whose milk was suckled?

Question:

Is it permissible to marry the granddaughter of a woman whose milk was suckled?

Answer:

Marriage is not permissible, because both are foster uncle and niece.
❀ The command of Allah the Almighty is:

﴿وَبَنَاتُ الْأُخْتِ﴾

“And the daughters of sisters (are also made unlawful for you).”
Here, the word “أخت” is general, which also includes foster sisters, therefore, marriage to a foster niece is not permissible, because the relationship that is prohibited by blood is also prohibited by suckling.
❀ Sayyida Aisha (may Allah be pleased with her) narrates that the Messenger of Allah (peace be upon him) said:

إن الرضاعة تحرم ما تحرم الولادة

“Suckling also makes unlawful those relationships that are made unlawful by birth (blood).”