Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works, saying, Blessed are they whose iniquities are forgiven, and whose sins are covered. Blessed is the man to whom the Lord will not impute sin.
There isn’t much in the way of expository songs from Romans 4. In fact, the best we have actually comes to us by way of Psalm 32:1-2, which Paul quotes in verses 7 and 8. This hymn was published anonymously in The New Metrical Version of the Psalms (1909):
How blest, those whose transgressions
have freely been forgiven;
whose guilt is wholly covered
before the sight of heaven.
Blest, those to whom our Lord God
will not impute their sin:
whose guilt has been forgiven;
whose hearts, made true again.
It could be sung to the tune of “The Church’s One Foundation.”