For this reason, one of the early generations said to his companion, “Remaining silent about evil is better than speaking it.” The other replied, “Speaking good is better than remaining silent about it.”
Allah Most High says:
“O you who believe, when you converse privately, do not converse in sin, aggression, and disobedience to the Messenger, but converse in righteousness and piety.”
He also says:
“There is no good in much of their private conversation, except for those who enjoin charity, kindness, or reconciliation between people. Whoever does this seeking Allah’s pleasure, We shall grant him a great reward.”
It is reported in the Sunan collections that the Prophet, peace and blessings be upon him, said:
“All the speech of the son of Adam counts against him, not for him, except enjoining what is right, forbidding what is wrong, or remembering Allah Most High.”
There are many hadiths concerning the virtues of silence, and likewise concerning the virtues of speaking good. Remaining silent when speech is obligatory—such as enjoining what is right and forbidding what is wrong—is forbidden, whether or not one adopts such silence as a religious observance. You must therefore love what Allah and His Messenger love, hate what Allah and His Messenger hate, regard as permissible what Allah and His Messenger have permitted, and regard as forbidden what Allah and His Messenger have forbidden.