I have talked with some people who were in the early church. (By “the early church,” we mean the religious culture [that prevailed] after the flood over many kingdoms, throughout Assyria, Mesopotamia, Syria, Ethiopia, Arabia, Libya, Egypt, Philistia as far as Tyre and Sidon, and the land of Canaan on both sides of the Jordan.) People then knew about the Lord who was going to come, and they absorbed the good qualities of faith; but nevertheless they did fall away and become idolaters. They are in the front toward the left in a dark area, and are in a sorry state. They have piping, monotone voices, and practically no rational thought. They said they had been there for centuries and that sometimes they were let out in order to be of some menial service to others.
This led me to reflect on the many Christians who are not idolaters outwardly but are inwardly because they actually worship themselves and the world, and at heart deny the Lord. This is the kind of lot that awaits them in the other life.
It has been explained in Section 308 that the Lord’s church is spread throughout the whole world. It is universal, then, and consists of all individuals who have lived in the virtue of thoughtfulness according to the principles of their religions. In relation to the people outside it, the church where the Word is and the Lord is known through it is like the heart and lungs of the human body, which give life to all the organs and members of the body according to their forms, locations, and connections.
from Heaven and Hell, Sections 327, 328