The problem with lines in the sand defining who’s “in” an “out” regarding salvation is that there are nearly as many lines as there are people. So, eventually, all you are really doing is choosing who’s line you are going to use to define your (and others) “salvation”. And whether that’s a small group of ONE congregation today, or a group of millions over 500 years makes little difference. It’s still ALL man’s opinion of what you “MUST believe” in order to be “saved”.
The Jews had THEIR ideas of what one needed to believe and do to please God. Jesus certainly challenged those. But then the disciples/apostles chose their OWN lines (for good or bad) for how one came to be “in Christ”. Paul, whom I consider to be the first “Christian universalist”, made some brilliant statements towards the inclusion of all, but STILL struggled with who was “saved” and who was “lost”.
I don’t think there ARE any lines, people. Everyone is “in Christ” because it’s not OUR choice that made for our inclusion. It was God’s plan from the beginning to “win us back” (reconcile us) to His heart after mankind decided that following rules would bring them back into favor with a God they decided was distant, authoritarian and retributive. Jesus challenged all THOSE ideas, too, and then showed us what God REALLY looks like — an innocent man, hanging on a cross at humanity’s hand, who comes back and proclaims peace rather than “justice” (vengeance) over mankind.
We are ALL included in the plan. There’s only knowing that you are vs. still being blind to the truth of it. The “sheep” and the “goats” (kids) are all of us and we are all at some times more “sheep” and at others more “goat”, but God’s love keeps refining away our “goat” attitudes and showing us that we are REALLY His sheep and always have been. We just “forgot”… or were lied to.
So, stop drawing lines and start recognizing the face of Christ in every person you meet, including your OWN in the mirror, whether they are considered “in” or “out” by the mass of “Christendom” or not. And let them KNOW that they are God’s precious sheep and He loves them, and is only FOR them. Especially this time of year when God declared His “GOODWILL” (favor, kindness, mercy, love) toward man by giving us an example of who He is in human flesh, so that we can learn and then also be Him in human flesh to the rest of our brothers and sisters.