That (the invisible Brahman) is full, this (the visible Brahman) is full. This full (visible Brahman) proceeds from that full (invisible Brahman). On grasping the fulness of this full (visible Brahman) there is left that full (invisible Brahman). Om (is) ether, (is) Brahman. 'There is the old ether (the invisible), and the (visible) ether of the atmosphere,' thus said Kauravyayaniputra. This (the Om) is the Veda (the means of knowledge), thus the Brahmanas know. One knows through it all that has to be known.

In plain words: That unseen reality is whole and complete, and this visible world is whole and complete too. The visible comes from the unseen, and when the whole is taken from the whole, the whole still remains. The sacred sound Om stands for Brahman, the ultimate reality, and through it one can know all that needs knowing.