When Peter comes to the door of the house where the disciples are praying for him, they think it’s Peter’s “angel” (Acts 12:15). The thing at the door is recognizably Peter, but they don’t think it’s Peter in the flesh. It’s still the person, but not the embodied person, so they believe.Aggeloshere means “ghost” or “soul” or “spirit” or whatever we might call that personal reality that remains after death.
The usage is intriguing, and it’s worth pausing over the fact that aggelos is used here. Fundamentally, the word means “messenger,” and can be used of human messengers who are not wraithy spirits. John the Baptist is an aggelos. The disciples praying for Peter think not only that Peter has appeared after death, but that he has appeared as a messenger bringing them news.