I read an article recently (linked on this forum) where it said that in heaven sin won’t be a possibility. Perhaps I misunderstood. So the idea is that if Lucifer had already experienced the beatific vision, pride would/could have never gotten a hold of him like it did?
I think there also is something else required on our part to enjoy the beatific vision. I am inclined to think as such because if that were not the case, God would have just given us all the beatific vision from the beginning.
So in the case of us humans, we fulfill this requirement by our lives here on earth. We try to conform ourselves to good. In the case of angels, this happened in a single moment. Some chose good while others chose to rebel.
Again, speaking from analogies, it might be like a person and marriage. Marriage is a good thing but for a person who has not conformed to good, it can appear disordered. It does not mean that marriage is not good but simply that the person cannot perceive it’s goodness.
So the Beatific Vision might be similar. It is intrinsically good and all that we desire but unless we have conformed ourselves to good on earth, we cannot see it. It is also possible that many of us never fully manage to conform ourselves to good but God perfects and purifies us before heaven so that by the time we do enter, we can fully appreciate the beatific vision. But what is important here is that we do need to accept God’s grace and conform ourselves sufficiently to good (God’s will) in order to be allowed in to heaven and enjoy the beatific vision. This also seems to present an explanation to those who do not enter heaven. It is not because God does not love them but simply because they cannot enjoy what God has in store for them (including the beatific vision) in heaven. They are the ones that have rejected God.
Now the question as to whether the fallen angles may have chosen differently, if we go along the lines of reasoning above, then the answer I think is no. In order to fully appreciate the beauty of the beatific vision, one needs to also be sufficiently ready to appreciate it. In the case of the fallen, they choose to rebel against conforming themselves to good in a singular moment. So unless they were born already GOOD, then they would not understand the value of the beatific vision. In this sense, one might even say the question is meaningless.
Again, this is just speculation and personal reflections on my part on how to reconcile things together. So it might be in error.
God Bless
