(Note: This post is a slightly edited version of an answer I originally wrote and posted on Christianity StackExchange. You can see the original question on StackExchange here, and the StackExchange version of my answer here.)
In Heaven: A History (1995: Yale University Press) the authors, Drs. Colleen McDannell and Bernhard Lang, state that Emanuel Swedenborg (1688–1772) had a pivotal role in bringing about a changed view of heaven, including the idea that angels are humans who have died and gone on to heaven, rather than a separate race of pre-created beings as mainstream Christianity had held for many centuries previously. See especially Chapter 7: “Swedenborg and the Emergence of a Modern Heaven.”
Swedenborg on humans becoming angels
Swedenborg based his teaching that all angels were once people primarily on his own experience of meeting and talking with them in the spiritual world. For example, he says in Heaven and Hell #311:
People in the Christian world are totally unaware that heaven and hell come from the human race. They actually believe that angels were created in the beginning and constitute heaven, and that the devil or Satan was an angel of light who became rebellious and was cast out together with his faction, and that this gave rise to hell.
Angels are utterly amazed that there can be this kind of belief in the Christian world, and even more so that people know absolutely nothing about heaven, even though this is a primary doctrine of the church. Knowing that this kind of ignorance is prevalent, they are profoundly delighted that it has now pleased the Lord to reveal to us so much about heaven—and about hell as well—and so as much as possible to dispel the darkness that is rising daily because this church is drawing to a close. So they want me to testify on their behalf that in all heaven there is not a single angel who was created as such in the beginning, nor is there in all hell a devil who was created as an angel of light and cast out. Rather, all the people in heaven and in hell are from the human race—in heaven the ones who have lived in heavenly love and faith, and in hell the ones who have lived in hellish love and faith.
The Bible on angels and people
Swedenborg also states, however, that this is the teaching of the Bible, if the Bible is properly understood. For a summary of the biblical arguments in favor of angels and devils as human beings who have died and gone on to the spiritual world, see the article “What is the Biblical Basis for Humans becoming Angels after they Die?”
Here are the basic points made in the article, accompanied by supporting references to the Bible:
- The Bible says nothing about angels being created.
- The Bible often refers to angels as “men.”
- Angels look like people.
- “Angel” means “messenger,” not a separate race of beings.
- Angels themselves reject the idea that they are superior beings.
- Jesus says that we become like angels after death.
For an introduction to Swedenborg’s teachings about angels, including a section on where angels come from, see “Who Are the Angels and How Do They Live?”
Swedenborg’s Heaven and Hell has been translated from its original Latin into many languages, and has had a large circulation throughout the world since it was first published in 1758 in London, England. Outside of various statements in the Bible itself, it is the primary source of the common modern belief that people become angels after death.
Note, however, that Swedenborg did not say that angels have wings. Rather, he said that they are fully human in appearance.
For further reading: