The Golus of the Shechinah:

The Kamarna Rebbe zy"a (Sefer Otzar Hachaim, Parshas Ki Seitzei) writes that it was revealed to him in a dream that the reason the Shechinah is in golus is because people do not watch their mouths and aren't careful not to speak pointless words and lashon hara. He explains that all words are given to man by the Shechinah, and when they are not used properly, the mouth becomes impure. When people who have defiled their mouths in this way try to daven, the forces of evil are able to grab away their words, thus sending the Shechinah into golus. He continues to say that the most important thing is to guard one's words. He bemoans the fact that every city in his times had a Rebbe, and the chasidim of each Rebbe felt that it was their duty to badmouth every other Rebbe.