Bhagavad Gita Chapter 13, Text 31

Bg 13.31

yada bhuta-prthag-bhavam
eka-stham anupasyati
tata eva ca vistaram
brahma sampadyate tada

Word for word: 
yada — when; bhuta — of living entities; prthak-bhavam — separated identities; eka-stham — situated in one; anupasyati — one tries to see through authority; tatah eva — thereafter; ca — also; vistaram — the expansion; brahma — the Absolute; sampadyate — he attains; tada — at that time.

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When a sensible man ceases to see different identities due to different material bodies and he sees how beings are expanded everywhere, he attains to the Brahman conception.

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When one can see that the various bodies of living entities arise due to the different desires of the individual soul and do not actually belong to the soul itself, one actually sees. In the material conception of life, we find someone a demigod, someone a human being, a dog, a cat, etc. This is material vision, not actual vision. This material differentiation is due to a material conception of life. After the destruction of the material body, the spirit soul is one. The spirit soul, due to contact with material nature, gets different types of bodies. When one can see this, he attains spiritual vision; thus being freed from differentiations like man, animal, big, low, etc., one becomes purified in his consciousness and able to develop Krishna consciousness in his spiritual identity. How he then sees things will be explained in the next verse.