The choir knows all about the blood of Christ. What the church needs to learn is that the grace of God in Christ, if you really have it, will have the consequence of transforming you into a person who lives righteously
Sure, discipleship should be always, deepening.
But good works do not prove you are born again.
They only prove you are doing good works.
The Devil's own, do a lot of good works, and so do his ministers and so do his denominations, and his bibles also contain enough of the Truth to offer some Good.
Dont get stuck on Good works, as your clue to someone's faith level.
Look instead at their belief system, and do they trust in Christ to keep them saved, or not.
Do they give Christ FULL CREDIT DUE HIM for saving them and keeping them saved.
Or do they not?
You dont.
And Right there is where you'll find the heretic vs the true believer.