Perhaps it is an understanding of what is meant by faith.
Many people claim to have faith but it’s only intellectual assent, not genuine trust that’s saving faith.
There are two ways of looking at the question.
One is that one persists in wantonly sinning as if nothing at all had happened in their conversion. And perhaps that’s what he was thinking of when he answered the question.
The other is that that we all do persist in our sins, although not wantonly. Yes, then faith still does save that person.
But I expounded on that some because we all sin all the time so in a sense, we are all persisting in our sins.
When we are born again, we are given a new sinless nature and yet the old sinful nature still resides in the flesh we inhabit. The new nature does not sin and hates sin. The old nature sins and loves it.
When we are weak, we tend to give in to the old nature more readily and hence, we sin. That grieves the new nature and sets up in us the stress that Paul described in Romans 7.
And even though we continue in sin and some people struggle mightily, the fact is, they struggle because they hate the sin.
If someone sins without the conscience being disturbed, they are not saved.
So, yes, we can and do persist in sin and are still saved.
But from another perspective, no, we cannot persist in wanton sin without the internal struggle and think we’re saved.
Believe it or not, what you have written is not far from what Catholics believe. Within Catholic theology, when we speak of faith we merely mean intellectual assent. Thus the importance we place on charity (love) and works, which are only made possible by faith. This is why I ask questions to try to get behind the vocabulary and understand what others actually believe.
Yes, we all do sin from time to time but if we turn back to God with sorrow for our sins and a sincere purpose of amendment (no matter how imperfect we know our actual efforts will be) then through faith our sins will be forgiven.
I am sure we will still disagree on how the sacraments of Baptism and Confession work in the scheme of things but there is no reason to invent disagreements where none exist.
You are correct MM. When I was a Catholic, way back in the last century, I must have committed 200 mortal sins a day, and never even had the smallest twinge of conscience. I sinned wantonly. Now that I am no longer a Catholic, and have saving faith, when I sin, I hate it, and it frustrates me. The old man still wars against the new man.