tata eva ca vistāraṁ
brahma sampadyate tadā
yadā—when; bhūta—living entities; pṛthak-bhāvam—separated entities; eka-stham—situated in one; anupaśyati—tries to see through authority; tataḥ eva—thereafter; ca—also; vistāram—expanded; brahma—the Absolute; sampadyate—attains; tadā—at that time.
When a sensible man ceases to see different identities, which are due to different material bodies, he attains to the Brahman conception. Thus he sees that beings are expanded everywhere.
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, this 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 beautified in his consciousness and able to develop Kṛṣṇa consciousness in his spiritual identity. How he then sees things will be explained in the next verse.
Link to this page: https://prabhupadabooks.com/bg/13/31