Superabundance of Grace
“But,” says he, “not as the offense so also is the free gift. For if, through the offense of one, many be dead, much more the grace of God, and the gift by grace, which is by One Man, Jesus Christ, has abounded unto many.” Not many more, that is, many more men, for there are not more persons justified than condemned; but it runs, much more has abounded; inasmuch as, while Adam produced sinners from his one sin, Christ has by His grace procured free forgiveness even for the sins which men have of their own accord added by actual transgression to the original sin in which they were born. This he states more clearly still in the sequel.
Source: Merits and Remission of Sin, and Infant Baptism (New Advent)