How did Vladimir Lenin and Joseph Stalin make sure their governments stayed in power?

Lenin consolidated his power through the Russian Civil War in which his army defeated the enemies of the revolution. He used terror to maintain and strengthen the state throughout the rest of his political life. On the other hand, Stalin ruled with an iron fist. He was ruthless and power hungry. He was a man whom power was all, and like Lenin he used terror as a useful weapon to obtain and keep his power.