The Predestination of the Saints/Gift of Perseverance

It would be too tedious to argue about the several points. But you see without doubt, you see with what evidence of apostolic declaration this grace is defended, in opposition to which human merits are set up, as if man should first give something for it to be recompensed to him again. Therefore God chose us in Christ before the foundation of the world, predestinating us to the adoption of children, not because we were going to be of ourselves holy and immaculate, but He chose and predestinated us that we might be so.

Moreover, He did this according to the good pleasure of His will, so that nobody might glory concerning his own will, but about God's will towards himself. He did this according to the riches of His grace, according to His good-will, which He purposed in His beloved Son; in whom we have obtained a share, being predestinated according to the purpose, not ours, but His, who works all things to such an extent as that He works in us to will also. Moreover, He works according to the counsel of His will, that we may be to the praise of His glory. For this reason it is that we cry that no one should glory in man, and, thus, not in himself; but whoever glories let him glory in the Lord, that he may be for the praise of His glory.

Because He Himself works according to His purpose that we may be to the praise of His glory, and, of course, holy and immaculate, for which purpose He called us, predestinating us before the foundation of the world. Out of this, His purpose, is that special calling of the elect for whom He co-works with all things for good, because they are called according to His purpose, and “the gifts and calling of God are without repentance.”