"The first and most basic concept is that of the all-pervasive Brahman — “Isavasyam idam sarvam yat kincha jagatyam jagat” (Whatever exists and wherever it exists is permeated by the same divine power.) While many philosophies have postulated unbridgeable dichotomies between god and the world, matter and spirit, the Upanishadic view is that all that exists is a manifestation without the light of consciousness behind it, and this, in a way, is the realization of the new science.
The second concept is that this Brahman resides within each individual consciousness, in the Atman. The Atman is the reflection of this all-pervasive Brahman in individual consciousness; but it is not ultimately separate from the Brahman. The concept of “Isvarah sarvabhutanam hriddese tishthati” (The lord resides within the heart of each individual) is the second great insight of the Upanishads, and the relationship between the Atman and the Brahman is the pivot upon which the whole Vedantic teaching revolves
Another important Vedantic concept is that all human beings, because of their shared spirituality, are members of a single family. The Upanishads have an extraordinary phrase for the human race, ‘Amritasya putrah’ (Children of immortality), because we carry within our consciousness the light and the power of the Brahman regardless of race, colour, creed, sex, caste or nationality. That is the basis of the concept of human beings as an extended family — ‘Vasudhaiva kutumbakam’