But will not man be careless about his duty to obey Christ when he is already well promised eternal salvation? I am sure that it will not. Even in human relationships, we don't need the threat of punishment to love those we love and honor those we honor. A wife can obey her husband and honor him, although he has once and for all firmly promised her that he will never leave her; Children can honor and obey their father, although they are firmly convinced that he will never turn them out of the house. It is the consciousness that God is our Father and Master, and that we are accepted among His children and servants, that obliges us to respectful obedience: the Son honors his father, and the servant honors his master; if I am a father, where is the reverence for me? and if I be the Lord, where is the reverence for me? says the Lord of hosts (Mal. 1:6).

When the Apostle says: "I subdue and enslave my body, lest, preaching to others, I myself remain unworthy" (1 Cor. 9:27), he does not show a slavish fear of losing salvation (he is sure of salvation: Phil. 1:21-23, 2 Tim. 4:8), but a filial fear of offending God and turning people away from the Good News by his unworthy behavior.

On Predestination to Salvation

He chose us in Him (in Christ) before the foundation of the world, that we might be holy and blameless before Him in love, having predestined us to be adopted as sons by Jesus Christ, according to the good pleasure of His will.

In Him we have become heirs, having been predestined for this by the decree of Him who does all things according to the purpose of His will (Ephesians 1:4-5, 11).

The Apostles clearly testify to this amazing truth: God chose us for salvation when we were not yet in the world, and the light itself did not yet exist. In the life of every believer, God fulfills His eternal plan: Peter, the Apostle of Jesus Christ, to the strangers scattered in Pontus, Galatia, Cappadocia, Asia and Bithynia, chosen, according to the foreknowledge of God the Father, sanctified by the Spirit, to obedience and to be sprinkled with the blood of Jesus Christ: Grace be unto you and peace abound (1 Peter 1:1-2).

For whom He foreknew, He also predestined to be conformed to the image of His Son, that He might be the firstborn among many brethren. And whom He predestined, He also called; and whom He called, He also justified; and those whom He justified, He also glorified (Romans 8:29-30).

God has not ordained us to wrath, but to receive salvation through our Lord Jesus Christ (1 Thessalonians 5:9).

But we must always thank God for you, beloved brethren of the Lord, that God from the beginning, through the sanctification of the Spirit and faith in the truth, has chosen you unto salvation, to which He also called you by our gospel, to attain to the glory of our Lord Jesus Christ (2 Thess. 2:13-14).

(labor by the power of God) who saved us, and called us with a holy calling, not according to our works, but according to his own purpose and grace, which was given to us in Christ Jesus before the ages (2 Tim. 1:9).

Thus, believers are predestined by God to salvation; The apostles want us to know this. Can a particular believer be sure that he is predestinated? As far as I can tell, it's hard to evade such confidence.

The Apostles address their epistles to those who are "called by foreknowledge" (1 Pet. 1:2), "chosen and predestinated" (Eph. 1:4-5), "ordained to be heirs" (Eph. 1:11), "ordained unto salvation" (1 Thess. 5:9), "from the beginning chosen unto salvation" (2 Thess. 2:13). If I am not chosen and predestined, then the Apostles did not write to me, and I simply should not read letters addressed to others. If, however, I accept the Apostolic Epistles as the word of God, addressed also to me personally, a word which I am also personally obliged to believe and obey, then I must also accept that predestination applies not only to other people, but also to myself personally.

The Apostles call us to be comforted by this in trials (Rom. 8:28-30), to bless God for it (Eph. 1:4-5), to rely on it in our Christian life (1 Thess. 5:9), to thank God for it (2 Thess. 2:13-14), as Blessed Augustine does: