The Wife of Your Brother Through Breast-feeding is Not One of Your Mahrams

Question :

Is it permissible for me to give salutations of peace to my maternal uncle's wife (my mother's brother), while I was breast-fed along with my maternal uncle by my grand- mother? Or is it forbidden because she is not a Mahram for me?

Answer:

It is not permissible for your maternal uncle's wife to touch your hand whether or not it is confirmed that you were breast-fed by your grandmother. This is because you are unrelated, i.e. you are not a Mahram to her. But as for giving salutations of peace according to the Sunnah, which is by speech, that is permissible; 'A'ishah, may Allah be pleased with her said, in explanation of the Verse of pledging allegiance to the Messenger for women: "By Allah, no woman's hand ever touched his hand during the pledge of allegiance; he did not take the pledge from them except by saying: 'I accept your pledge to this."Narrated by Al-Bukhari.

It is reported on the authority of Umaimah Bint Ruqayyah, may Allah be pleased with her, that she said: "I came to the Messenger of Allah with some women to make the pledge of allegiance to him and we said: "O Messenger of Allah! Will you not shake hands with us?" He replied:

"Verily, I do not shake hands with women. My saying to one woman is the same as my saying to a hundred women."

Narrated by Ahmad with an authentic chain of narrators.

Source:
The Permanent Committee
Fatawa Islamiyah, Vol. 6 Pages 156-157