The verse says that “All of the work of a person is for his mouth!”, and Chazal explained that all of the good deeds and commandments that a person has done are not enough to atone for him having sinned with his mouth. It says further that “One who guards his mouth and tongue guards his soul from trouble” and that “Death and life are in the “hand” of the tongue!”. This is because many of the sins and iniquities which are committed by the mouth have become permitted to many people. These include Lashon Hara (saying bad about others), flattery, speaking rudely, lying, swearing in vain, mentioning the Name of Hashem in vain, and many others. Speaking idly is the worst of all. One who commits these iniquities does not even think that he has sinned when actually they are very severe sins.
Go out and learn from that which Chazal said about idle speech, as the Midrash says that Hashem said “Creating the world was not tiring for Me (as it says “He will not tire or be weary”). What is tiring for Me? One who makes Me angry with idle speech (as it says Hashem became tired with your words”).” If that is the case with plain idle speech how much more is it true when one mixes it with other prohibitions, that it then becomes very severe!
