1 Peter 5:8-9 says,
“Be sober-minded; be watchful. Your adversary the devil prowls around like a roaring lion, seeking someone to devour. Resist him, firm in your faith, knowing that the same kinds of suffering are being experienced by your brotherhood throughout the world.”
But if the fundamental tenet of ‘Once Saved, Always Saved’ (OSAS) – that once a person is saved, they are unconditionally always and forever saved – is correct, why should we be sober-minded and watchful? After all, if OSAS was correct, the devil prowling around like a roaring lion seeking someone to devour can’t affect our eternal destiny. Even if he does manage to devour us, we will still be saved, according to OSAS. Notable OSAS advocate Charles Stanley writes,
“[T]he unfaithful believer will not lose his salvation … Even if a believer for all practical purposes becomes an unbeliever, his salvation is not in jeopardy … Christ will not deny an unbelieving Christian his or her salvation … believers who lose or abandon their faith will retain their salvation, for God remains faithful.” 1
And furthermore, who is the devil seeking to devour, and what’s the point? It makes no sense that he would be seeking to devour unsaved people – they’re already the sons of disobedience, and because they believe not, they are already under condemnation (see John 3:18; Eph. 2:2). If OSAS was true, it makes no sense that he would try and devour saved people – he’s had long enough to study the Scriptures, and if he knew that OSAS was true, why would he try and devour someone whose salvation cannot possibly be put in jeopardy, even if they resume a state of unbelief?
The only view which can make sense of 1 Peter 5:8-9 is the view which affirms that true believers can in fact apostatize, and come under condemnation. That’s why the devil is prowling around – he knows that though the spirit may be willing, the flesh is weak. He knows that if he can get someone to sow to the flesh, they will reap destruction (Gal. 6:7-9). He knows that if he can get someone to stop standing by faith in God’s kindness, they will fall and come under God’s severe judgement (Rom. 11:17-22). He knows that if he can get people to live according to the flesh, they will die (Rom. 8:12-14), and have no inheritance in the kingdom of God (1 Cor. 6:9-10).
So why should believers be sober-minded and watchful? Because our eternal destiny is at stake. We must continue in the faith, stable and steadfast, if we are to be presented holy and blameless before God (Col. 1:21-23). We must be holy, if we are to see God in the end (Heb. 12:14). We must continue abiding in Christ, if we are to avoid being cut off and thrown into the fire (John 15:1-6).
The Gospel is about the ‘Way’ of salvation, along which we must travel, if we are to reach our destination; the Christian life is about the ‘race,’ in which we must run, if we are to receive our prize (cf. 1 Cor. 9:24; 2 Tim. 4:7; Heb. 12:1).
May we never let anyone deceive us into thinking that such a thing exists as an ‘unbelieving Christian’ or a ‘saved unbeliever’ (a contradiction in terms if ever there was one).
May we never let anyone deceive us into thinking that we can abandon our faith and yet still retain our share in God’s household (see Heb. 3:6). May we never be deceived into thinking that we can have an evil heart of unbelief, while remaining partakers of Christ (see Heb. 3:12-19). May we never let anyone deceive us into thinking that we can become unbelievers without our salvation being put in jeopardy (cf. Ezek. 18:24-26; Rom. 1:18; 11:20-21; 1 Cor. 6:9-10; 2 Cor. 6:14-15; Heb. 3:12-19; Rev. 21:8).
Rather, let us continue on the ‘Way’; let us run with endurance the race set before us; let us strive for holiness, for without holiness, no one will see the Lord; and let us be sober-minded, let us be watchful, for our adversary the devil prowls around like a roaring lion, seeking someone to devour. If we are not careful, that someone could be us. Our eternal inheritance is a high price to pay for our spiritual neglect.
1 Charles Stanley, Eternal Security: Can You Be Sure? (1990, Thomas Nelson), pp. 92-94