In the matrix, caused by māya, the relative reality, the knowledge is also given, to give consciousness the chance to get to know itself. This self-knowledge is the special condition of a jñānī, a knower who knows that his personality (puruṣa) is mithyā. Consciousness itself is attributeless and therefore knowledgeless, thoughtless. Consciousness itself is pure knowledge in itself. Thus the jñānī views the man who appears in him as a false appearance of himself, consciousness. That's the joke of existence.

This knowledge comes from god (īśvara), because īśvara is all knowledge (sarvajña), both apparent ignorance and knowingness?

We only have to look at our own lives. Who comes up with the idea that in reality you are the only thing that is, infinite, without any quality, free, full, whole, complete, radiant consciousness, like being itself.

Hence the importance of following the Vedas (āstika). The Vedas are the means of knowledge that points to our nature as the 'being' (asti, it is) itself.