If you are angry, and then happy, the next moment the anger passes away. Out of that anger you manufactured the next state. These states are always interchangeable. Eternal happiness and misery are a child's dream.
Swami VivekanandaIt is the free alone which never changes, and the unchangeable alone which is free; for change is produced by something exterior to a thing, or within itself, which is more powerful than the surroundings.
Swami VivekanandaThe correct meaning of the statement The Vedas are beginningless and eternal is that the law or truth revealed by them is permanent and changeless.
Swami Vivekananda