। ॥ ६२१ ॥
In plain words
Not depending on any external light, because it shines entirely by its own nature, this consciousness-Self is self-luminous. For the shining of the Self never requires any other light.
Close to the Sanskrit
Not depending upon any other light at all, because this shines by its own nature indeed, therefore this consciousness-Self is self-luminous. Indeed, there is no need of another light in the shining of the Self.