Why were massive repressions launched and what results did they have?

Mass repressions in the USSR began with the coming to power of Stalin. His goal was to establish the sole authority in the country, which he was able to achieve. To retain this power, it was necessary to fight all dissidents. Repression was applied to them. There were many dissidents, so the repression became widespread. Representatives of the church were exposed to them, since Stalin did not want the propaganda of an ideology other than the state. The repression resulted in great human sacrifice, the creation of a society in which everyone adheres to the same point of view.