Musnad Ahmad 1170:4

'Abd al-Rahman ibn Mahdi narrated to us, he said: Sufyan narrated to us, from Muhammad—meaning Ibn al-Munkadir—from Umaymah bint Ruqayqah, she said: I came to the Prophet, may Allah bless him and grant him peace, among a group of women to pledge allegiance to him. He took from us what is in the Qur'an: that we do not associate anything with Allah—the verse. He said: "In what you are able and capable of." We said: "Allah and His Messenger are more merciful to us than we are to ourselves." We said: "O Messenger of Allah, will you not shake our hands?" He said: "I do not shake hands with women; my word to one woman is like my word to one hundred women."