Summing up the teaching of Upanishad Dr Radhakrishnan says
God’s dwelling place is in the heart of man. The inner immortal soul and the great cosmic power are one and the same. Brahman is Atman and Atman is Brahman.
We have to remember that the highest religion of the Upanishads, which insists on meditation and morality and worship of God in spirit and truth, is not encumbered by such traditional dogmas and miracles as still hang upon the skirts of other religions. Its central principle that there is one supreme reality that manifests itself in the universe is not asserted as a dogma. It is the ultimate truth at which it is possible for human understanding to arrive. The progress of science and philosophy does not conflict with it but only confirms it.
Dr S Radhakrishnan