How does one discover one’s true identity? Through the purification of our mind.
The Atman is ever pure; it needs no purification. It is only the mind that has to be purified and not Atman.
When we say we are impure, it is not about the Atman but the mind which has to be made pure.
Impurity of mind originates in misunderstanding our real nature. This misunderstanding has to be corrected.
It is not that we have to become Atman; we are already that. What we need is to remove the false covering on our true being.
(Source: Human Values by Swami Visharadananda. Page 102)