The essential Vedic teachings on the universal nature of personality are summarized in Sri Isopanisad, the foremost of the 108 Upanisads.
"Because we do not know that there is a complete arrangement in nature for our maintenance, we make efforts to utilize the resources of nature to create a so-called complete life of sense enjoyment. Because the living entity cannot enjoy the life of the senses without being dovetailed with the complete whole, the misleading life of sense enjoyment is illusion. The hand of a body is a complete unit only as long as it is attached to the complete body. When the hand is severed from the body, it may appear like a hand, but it actually has none of the potencies of a hand. Similarly, living beings are part and parcel of the Complete Whole, and if they are severed from the Complete Whole, the illusory representation of completeness cannot fully satisfy them.
The completeness of human life can be realized only when one engages in the service of the Complete Whole. All services in this world--whether social, political, communal, international or even interplanetary--will remain incomplete until they are dovetailed with the Complete Whole. When everything is dovetailed with the Complete Whole, the attached parts and parcels also become complete in themselves." From Sri Isopanasad Invocation.