Riyad us Saliheen: Hadith 1800

Abu Bakr (May Allah be pleased with him) came upon a woman named Zainab from the Ahmas tribe and noticed that she was observing total silence. He said: "What has happened to her? Why does she not speak?'' People informed him that she had sworn to remain silent. He then said to her: "You should speak, it is not permissible (to observe silence), for it is an act of the Days of Ignorance (Jahiliyyah)." (After hearing this) she started speaking.

[Al-Bukhari].