The proverb is referring to a heavenly existence for those who have been found to be sufficiently righteous but not sufficient for enlightenment. Existence is not the same as merging; that is usually referred to as sitting on the throne of the Divine Self. The causal realm is where relative existence is engendered. Therefore, reverting to this level of existence is a precursor to absorption (using these analogies). Indeed these are varying levels of closeness to the Divine and occurring within time and space.