A man is said to be [illumined] if his will has become firm, if his mind is not disturbed by misery, if he does not desire any happiness, if he is fr… - Swami Vivekananda

Knowledge can only be got in one way, the way of experience; there is no other way to know.

26. स पूर्वेषाम् अपि गुरुः कालेनानवच्छेदात् ॥ २६ ॥
sa poorvesham api guruh kalenanavachchhedat
He is the Teacher of even the ancient teachers, being not limited by time. It is true that all knowledge is within ourselves, but this has to be called forth by another knowledge. Although the capacity to know is inside us, it must be called out, and that calling out of knowledge can only be got, a Yogi maintains, through another knowledge. Dead, insentient matter, never calls out knowledge. It is the action of knowledge that brings out knowledge. Knowing beings must be with us to call forth what is in us, so these teachers were always necessary. The world was never without them, and no knowledge can come without them. God is the Teacher of all teachers, because these teachers, however great they may have been—gods or angels—were all bound and limited by time, and God is not limited by time. ...

God is self-evident, impersonal, omniscient, the Knower and the Master of nature, the Lord of all. He is behind all worship and it is being done according to Him, whether we know it or not.