tell me how David's murder and adultery in the matter of Bathsheba and Uriah were forgiven.
This really gets to the heart of the issue. David understood what Paul teaches in Romans. Or I should say, Paul knew and understood what David was saying, after his call by Jesus on the road to damascus.
To be sure, David was pre cross, and could only look forward. But he, like Paul knew who the blessed man was and is. Paul quotes Psalm 32 in his argument that justification is by faith alone.
"What then shall we say was gained by Abraham, our forefather
according to the flesh? 2 For if Abraham was justified by works, he has something to boast about, but not before God. 3 For what does the Scripture say? “Abraham believed God, and it was counted to him as righteousness.” 4 Now w to the one who works, his wages are not counted as a gift but as his due. 5 And to the one who does not work but believes in him who justifies the ungodly, his faith is counted as righteousness,
6 just as David also speaks of the blessing of the one to whom God counts righteousness apart from works:
7 “Blessed are those whose lawless deeds are forgiven,
and whose sins are covered;
8 blessed is the man against whom the Lord will not count his sin.”
9 Is this blessing then only for a the circumcised, or also for the uncircumcised? For we say that faith was counted to Abraham as righteousness. 10 How then was it counted to him? Was it before or after he had been circumcised? It was not after, but before he was circumcised. 11 He received the sign of circumcision as a seal of the righteousness that he had by faith while he was still uncircumcised. The purpose was to make him the father of all who believe without being circumcised, so that righteousness would be counted to
2 Samuel 12:13
So David said to Nathan, "I have sinned against the LORD." And Nathan said to David, "The LORD also has put away your sin; you shall not die.
I love that verse.. The Lord has put away your (my) sin, what a great comfort to us all.
Paul use's David in Psalm 32, in his aegument for Justification by faith apart from works in Romans 4..
As David and Paul say:
Blessed is the one whose transgression is forgiven,
Whose sin is covered. 2 Blessed is the man against whom the LORD counts no iniquity, and in whose spirit there is no deceit.
...
5 I acknowledged my sin to you, and I did not cover my iniquity; I said, “I will confess my transgressions to the LORD,” and you forgave the iniquity of my sin.