Apparently it’s not.
If you are saved, then you sin, then you are no longer saved anymore and you are condemned to hell.
Ergo, once saved, always saved is a myth.
So you would say that Christs sacrifice, unlike the sacrifices in the Old Testament Temple, is not the atonement for sins? You would also say that Christ was not the perfect, once for all sacrifice but that men have to finish what He started?