John Gill Commentary Romans 4:8

"Blessed is the man to whom, the Lord will not reckon sin." — Romans 4:8 (ASV)

Blessed is the man to whom the Lord will not impute sin .
] As he does not to those whom he justifies in Christ, and by his righteousness; for the sins of such he has imputed to his Son, as their surety; and he has bore them, took them away, having made full satisfaction for them; so that these persons will never be charged with them:

they now appear before the throne without fault, and are blameless and irreprehensible in the sight of God, and therefore must be eternally happy; for he will never think of their sins any more to their hurt; he will remember them no more; he "will never reckon them to them", but acquit them from them, justify and accept them; wherefore they must be secure from wrath and condemnation, enjoy much peace and comfort now, and be happy hereafter.