Impersonalism can cause even the greatest to fall back to the material world

Brahma and the great rsis and the great master of yoga (Siva) are not ordinary

living entities; they are very powerful and have all the perfections of

mystic yoga. But still they have an inclination to try to become one with

the Supreme, and therefore they have to come back. In the Srimad Bhagavatam

it is accepted that as long as one thinks that he is equal

with the Supreme Personality of Godhead, he is not completely purified or

knowledgeable. In spite of going up to the first purusa-avatara, Maha-

Visnu, after the dissolution of this material creation, such

personalities again fall down or come back to the material creation.

It is a great falldown on the part of the impersonalists to think that

the Supreme Lord appears within a material body and that one should

therefore not meditate upon the form of the Supreme but should meditate

instead on the formless. For this particular mistake, even the great

mystic yogis or great stalwart transcendentalists also come back again

when there is creation.

Srimad Bhagavatam 3.32.15 purport