Yoga Sutras of Patanjali 2.5

2.5

anityāśuciduḥkhānātmasu nityaśucisukhātmakhyātir avidyā ||

The darkness of ignorance is: holding that which is unenduring, impure, full of pain, not the Soul, to be eternal, pure, full of joy, the Soul.

This we have really considered already. The psychic man is unenduring, impure, full of pain, not the Soul, not the real Self. The spiritual man is enduring, pure, full of joy, the real Self. The darkness of unwisdom is, therefore, the self-absorption of the psychical, personal man, to the exclusion of the spiritual man. It is the belief, carried into action, that the personal man is the real man, the man for whom we should toil, for whom we should build, for whom we should live. This is that psychical man of whom it is said: he that soweth to the flesh, shall of the flesh reap corruption.