Prohibition of observing silence from Dawn till Night

'Ali (May Allah be pleased with him) said: I have retained in my memory the saying of the Messenger of Allah (PBUH) that: "No one is considered an orphan after he has attained the age of maturity; and it is unlawful to remain silent from dawn till night."

Qais bin Abu Hazim (May Allah be pleased with him) said: 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.