nimitte sati sarvatra
jaladav api purusah
atmanas ca parasyapi
bhidam pasyati nanyada
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Only because of different causes does a person see a difference between himself and others, just as one sees the reflection of a body appearing differently manifested on water, on oil or in a mirror.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The spirit soul is one, the Supreme Personality of Godhead. He is manifested in svamsa and vibhinnamsa expansions. The jivas are vibhinnamsa expansions; the different incarnations of the Supreme Personality of Godhead are svamsa expansions. Thus there are different potencies of the Supreme Lord, and there are different expansions of the different potencies. In this way, for different reasons there are different expansions of the same one principle, the Supreme Personality of Godhead. This understanding is real knowledge, but when the living entity is covered by the upadhi, or designated body, he sees differences, exactly as one sees differences in reflections of oneself on water, on oil or in a mirror. When something is reflected on the water, it appears to be moving. When it is reflected on ice, it appears fixed. When it is reflected on oil, it appears hazy. The subject is one, but under different conditions it appears differently. When the qualifying factor is taken away, the whole appears to be one. In other words, when one comes to the paramahamsa or perfectional stage of life by practicing bhakti-yoga, he sees only Krsna everywhere. For him there is no other objective.
In conclusion, due to different causes, the living entity is visible in different forms as an animal, human being, demigod, tree, etc. Actually every living entity is the marginal potency of the Supreme Lord. In Bhagavad-gita (5.18), therefore, it is explained that one who actually sees the spirit soul does not distinguish between a learned brahmana and a dog, an elephant or a cow. Panditah sama-darsinah: one who is actually learned sees only the living entity, not the outward covering. Differentiation is therefore the result of different karma, or fruitive activities, and when we stop fruitive activities, turning them into acts of devotion, we can understand that we are not different from anyone else, regardless of the form. This is only possible in Krsna consciousness. In this movement there are many different races of men from all parts of the world participating, but because they think of themselves as servants of the Supreme Personality of Godhead, they do not differentiate between black and white, yellow and red. The Krsna consciousness movement is therefore the only means to make the living entities free of all designations.