Celsus next addresses to us the following remark: “You will not, I suppose, say of him, that, after failing to gain over those who were in this world, he went to Hades to gain over those who were there.” But whether he like it or not, we assert that not only while Jesus was in the body did He win over not a few persons merely, but so great a number, that a conspiracy was formed against Him on account of the multitude of His followers; but also, that when He became a soul, without the covering of the body, He dwelt among those souls which were without bodily covering, converting such of them as were willing to Himself, or those whom He saw, for reasons known to Him alone, to be better adapted to such a course.
Source: Against Celsus (New Advent)