Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: When the women pledged allegiance on the condition that they would not display their adornment like the display of the former times of ignorance, a woman said: O Messenger of Allah, I see that you are making it a condition upon us that we do not display our adornment, but such-and-such a woman helped me (in lamentation), and now her brother has died. The Messenger of Allah (peace and blessings be upon him) said: "Go and help her (in lamentation), then come and pledge allegiance to me."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11638