Sometimes there is a misunderstanding and you know there is but your silence helps the misunderstanding to endure.
Sometimes you know a truth but your silence just helps the truth to be hidden longer.
Sometimes you see another person is in an immediate danger, but you still stay silent.
Sometimes, it takes courage not to be silent and your fear of failure or rejection keeps you silent.
Silence denies, silence avoids, silence hides, silence fears and this kind of silence is a sin and hurts you and others.
I don't say silence is always bad, there are times that silence is wiser.
In every situation, based on the level of your wisdom as well as your courage, you decide whether to stay silent; when, where and with whom.