12-16

Because the upright, when they go to the next life, at first
return to the life they had in this world and so to what
they loved and relished during that life, they cannot associate with angels yet, not even in their breathing. First
they have to be prepared. In the course of preparation
they are introduced to angelic life through synchronized
breathing, during which they come to enjoy inner perceptions and heavenly freedom. This usually happens in
company or in choruses, in which each individual resembles the next in respiration, perception, and freedom
of action. I was shown how this was done, again through
firsthand experience.
—Secrets of Heaven 3894b