The Buddha taught us that any teaching that abides by the following three characteristics, the THREE DHARMA SEALS, can be validated as a true teaching of the Buddha:

Anicca (IMPERMANENCE): All phenomena, whether mental or physical, undergo constant changes. All living and non-living elements are subject to decay and destruction.

Anatta (NON-SELF): All phenomena are without a separate and permanent self. Everything in the universe is made up of parts. There is no single fixed component of anything that is not subject to change. It means everything is interconnected and interdependent on each other.

Nirvana (ENLIGHTENMENT): It is the complete extinction of all concepts and phenomena to arrive at True Peace. It means the pacifying, silencing or extinguishing of the fire of suffering. We only need to return to our true nature (Buddha-nature) to experience true happiness.