Either they weren’t Christians or they’re not an atheist.
You’re denying reality. They
were Christians. They now
are not Christians.
Salvation requires that we know Jesus Christ. You cannot know Christ and then not believe in Christ.
Yes you can. People do it all the time. We live in time. We grow and change. The things of childhood and youth become forgotten. A youth can have a very strong relationship with Christ during the college and early career years. Then, something happens that pulls him away from the practice of his faith - he falls in love with someone who does not share his beliefs, or he gets a job that requires him to be in remote places where there are no churches, or he simply becomes busy with the day to day of staying alive in this material world. The things of youth, including his relationship with Christ, are first neglected, and then entirely forgotten.
If you were with someone all day every day for months on end, then you had a relationship with them, right? But, if you haven’t spoken to them in 20 or more years, then you no longer have that relationship, do you?
That’s how it is with some people, and Jesus. They have a relationship with Him when they are young, and then when they get older, they lose it. Losing it doesn’t mean that they never had it, though.
Either you didn’t know Him then, or you cannot honestly say that you do not believe in Him now.
And yet, it happens.
And how would you know this?
Because they told me, and because I lived with them and saw how they lived. They were definitely Christians. They were not pretending in public, and then doing something else in private, and they certainly weren’t trying to impress anyone.
Did you know that the Bible tells us that there are false converts? People who live a Christian-like life, but who are not saved?
Of course, but these people were
never just pretending.
But that they’re living a sinful lifestyle isn’t evidence that they’re not saved, the Bible says that it’s evidence they never were saved.
Then why does St. Paul continually warn Christians not to fall away? If we
can’t fall away, then why discuss the ways to avoid this at such great length, in every letter of his?