They Who Have Not Received Perseverance are Not Distinguished from the Mass of Those that are Lost
And, consequently, both those who have not heard the gospel, and those who, having heard it and been changed by it for the better, have not received perseverance, and those who, having heard the gospel, have refused to come to Christ, that is, to believe in Him, since He Himself says, “No man comes unto me, except it were given him of my Father,” and those who by their tender age were unable to believe, but might be absolved from original sin by the sole laver of regeneration, and yet have not received this laver, and have perished in death: are not made to differ from that lump which it is plain is condemned, as all go from one into condemnation. Some are made to differ, however, not by their own merits, but by the grace of the Mediator; that is to say, they are justified freely in the blood of the second Adam. Therefore, when we hear, “For who makes you to differ? And what have you that you have not received? Now, if you have received it, why do you glory as if you had not received it?” we ought to understand that from that mass of perdition which originated through the first Adam, no one can be made to differ except he who has this gift, which whosoever has, has received by the grace of the Saviour. And this testimony is so great, that the blessed Cyprian writing to Quirinus put it in the place of a title, when he says, “That we must boast in nothing, since nothing is our own.”
Chapter 13.— Election is of Grace, Not of Merit.
Whosoever, then, are made to differ from that original condemnation by such bounty of divine grace, there is no doubt but that for such it is provided that they should hear the gospel, and when they hear they believe, and in the faith which works by love they persevere unto the end; and if, perchance, they deviate from the way, when they are rebuked they are amended and some of them, although they may not be rebuked by men, return into the path which they had left; and some who have received grace in any age whatever are withdrawn from the perils of this life by swiftness of death. For He works all these things in them who made them vessels of mercy, who also elected them in His Son before the foundation of the world by the election of grace: “And if by grace, then is it no more of works, otherwise grace is no more grace.” For they were not so called as not to be elected, in respect of which it is said, “For many are called but few are elected;” but because they were called according to the purpose, they are of a certainty also elected by the election, as it is said, of grace, not of any precedent merits of theirs, because to them grace is all merit.
Source: On Rebuke and Grace (New Advent)