David,
Wow!
Since I had been one of the people who had once promoted a "repentance-less" gospel, I really enjoyed reading your letter.
Also, you brought up Psalm 139:23-24.
I've wonder many times, if David had not uttered that (& wrote that), before his sin with Bathsheba & Uriah.
If it was, then his prayer was answered, the "hard way".
Gino