It is strange that a person may find it easy to protect himself from: eating Haraam, oppression and injustice, adultery, theft, drinking khamr (alcoholic drinks), and from unlawful looking, but it is hard for him to restrain the movement of his tongue. How often do we see people who are very cautious about falling into shameful deeds or injustice, but their tongue lashes against the living and the dead and they don't mind it?
Ibn Taymiyyah