The veil of Avidya separates us from God. Algae grows in water and then envelops the water. In the same way, Avidya draws its existence and sustenance from Pure Consciousness and covers It.
Just as light dispels darkness. Avidya is dispelled by Vidya. You have been a witness to countless events of sorrow and happiness and have been through numerous bodies in your previous lives, but one thing that remains ever existent is You, the Atman. To consider the Avidyamaana the body, objects, pains and pleasures to be Vidyamaana, and remaining unaware of the only Vidyamaana entity -the Brahman, is called Avidya.
Lord Sri Krishna has thus clarified the Avidyamaana in his discourse to Arjuna,
If you dont kill these kings and princes, will they live forever? They will perish in any case. Being parts of the Supreme Consciousness they existed in the past, are there in the present, and will forever remain there.
One established in Self-knowledge incurs no sins even if he destroys the three worlds.