Yoga Sutra Patanjali 01.18-19: The Soul Mystery. Soul is always a mystery. The enlightening mind can only grab a glimpse of radiance of Soul but not the whole truth of Soul. The state of enlightenment is also not an instant; it needs some processes to know the very nature of things.
Lesser enlightenment if there is two identities, such as someone can speak with angel, get message from other dimension. But Patanjali mentions the higher level, which is accompanied by knowingness not only knowledge.
Knowledge based on your collection get from books and people. Knowingness is based on your own experiences.