Now, inevitably, each reader has his own way of expressing how this works, but regardless of exactly how we connect our own efforts with God’s efforts, it’s clear that Paul is insisting on both human effort and divine effort.
Now, is he insisting on human effort to please God or to earn our salvation? Well, plainly we can’t earn our salvation. But then, neither can we refuse Paul’s instruction to be blameless and completely holy.
It gets tiresome arguing over just the right way to say this, when all sides agree that we are saved by the work of Jesus and the faithfulness of God to his covenant to count faith as righteousness — but we also are obligated to grow in holiness, which is not easy.
As Paul began the letter with prayer and thanksgiving, focused on the work of the one God through Jesus the Messiah in Thessalonica, so he ends it the same way. The God of peace—a favourite title of God for Paul—is the one who will make his people holy, so that they will be blameless at the coming of Jesus. Of course, part of the means by which he will do this is the thinking, suffering and struggling of the people themselves. This is the balance that we must maintain at the heart of all Christian living. To be holy is hard work, but we believe that it is God himself, present in our hearts by the spirit, who enables us to get on and do it. Paul doesn’t suggest that only a reasonable amount of holiness is required; it must be complete. Some Christians, emphasizing the boundless love of God and the doctrine of justification by faith apart from works, run the risk of underestimating the call of holiness, which Paul—who is after all the great exponent of God’s love and of free justification—never did.
Tom Wright, Paul for Everyone: Galatians and Thessalonians, (London: Society for Promoting Christian Knowledge, 2004), 134.
To me (and there are many other ways of saying much the same thing) the key is to remember that we are saved by faith in Jesus. (Please don’t fill up the comments with tract material on baptism. I’m speaking of Christians.) Some err in seeing faith as sufficient to justify, meaning to move someone from a damned condition to a saved condition, but not sufficient to keep us saved thereafter. These people argue that salvation becomes a works salvation after initial justification. But the scriptures say,
(Hab. 2:4 ESV) 4 “Behold, his soul is puffed up; it is not upright within him, but the righteous shall live by his faith.”
(Gal. 3:11 ESV) 11 Now it is evident that no one is justified before God by the law, for “The righteous shall live [indicative future] by faith.”
(Heb. 10:36-39 ESV) 36 For you have need of endurance, so that when you have done the will of God you may receive what is promised. 37 For, “Yet a little while, and the coming one will come and will not delay; 38 but my righteous one shall live [future indicative] by faith, and if he shrinks back, my soul has no pleasure in him.” 39 But we are not of those who shrink back and are destroyed, but of those who have faith and preserve their souls.
The future indicative voice speaks to what will happen in the future. “Live by faith” does no look backwards to the moment of justification but to the future — in fact, all the way to the Second Coming, when we are either destroyed or “have faith” (Heb 10:39).
Countless other passages are to the same effect. Faith is not only the pathway into salvation, faith in Jesus keeps us saved.
The trick is to remember that “faith” in the scriptures has three elements: belief that Jesus is the Messiah and Lord, trust in Jesus and God to be faithful to their promises, and faithfulness to Jesus and God. In Greek, “faithfulness” is the very same word as “faith.”
Faithfulness is all about the state of my heart. If my heart is faithful (Moses would say “circumcised”: Deu 10:16; 30:6), then I’ll obey God — to the extent of my knowledge of God’s will. Not perfectly, of course, but well enough to be fairly called obedient or penitent (which also refer to the state of one’s heart). If I’m incorrectly instructed on how to organize a church, then I’ll likely do that in error, but I’ll still be faithful because I’m still intending to honor God’s commands. Rom 14 is quite clear on this very point — following 11 chapters on the sufficiency of faith in Jesus to save.
Now, some would object to a subjective standard for faithfulness, fearing that this would undermine faith itself — so that someone could be forgiven for worshiping an idol rather than God if he was sincere. But such a person would not meet the definition of “faith” — which includes belief that Jesus is Messiah and Lord. Only those with faith in Jesus are in grace and so qualify to be judged in this subjective manner.
We also have this Enlightenment fear of the subjective, wanting to insist on scientific, rational, objective truths as a way to escape the dangers of relying on emotions. But the Bible is not an Enlightenment document, and it speaks over and over to the heart.
(Joel 2:11-13 ESV) 11 The LORD utters his voice before his army, for his camp is exceedingly great; he who executes his word is powerful. For the day of the LORD is great and very awesome; who can endure it? 12 “Yet even now,” declares the LORD, “return to me with all your heart, with fasting, with weeping, and with mourning; 13 and rend your hearts and not your garments.” Return to the LORD your God, for he is gracious and merciful, slow to anger, and abounding in steadfast love; and he relents over disaster.”
(Matt. 5:8 ESV) 8 “Blessed are the pure in heart, for they shall see God.”
(Matt. 22:37 ESV) 37 And he said to him, “You shall love the Lord your God with all your heart and with all your soul and with all your mind.
Moreover, many of us stumble into a Gnostic, dualistic worldview, imagining that while our emotions are unreliable, our intellects are capable of perfect understanding, especially when it comes to doctrine. Therefore, we grant grace for moral sin but not for doctrinal sin. But we are fallen creatures — body, spirit, soul, and mind. Nothing in us is going to be perfect before Jesus returns. And even our intellects make mistakes. I mean, if everyone is capable of perfect doctrinal understanding, why doesn’t everyone make a 100 on every test in school? Why do we forget things? It’s just so unrealistic … Our God knows us better than we know ourselves, and so he’s given us a path to salvation that works for the imperfect.
Now, the truly Christian perspective all comes together very nicely when you realize that the primary work of the Spirit in the Christian is to influence his heart — the very thing needed to be faithful/trust/have faith —
(Jer. 31:33-34 ESV) 33 For this is the covenant that I will make with the house of Israel after those days, declares the LORD: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people. 34 And no longer shall each one teach his neighbor and each his brother, saying, ‘Know the LORD,’ for they shall all know me, from the least of them to the greatest, declares the LORD. For I will forgive their iniquity, and I will remember their sin no more.”
(Ezek. 36:26-27 ESV) 26 And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. 27 And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.
(Rom. 2:29 ESV) But a Jew is one inwardly, and circumcision is a matter of the heart, by the Spirit, not by the letter. His praise is not from man but from God.
The Prophets declare that God will change our hearts by giving us his Spirit in our hearts, and the result will be that we become obedient and will be forgiven of our sins.
God does it, through the Spirit, so that we’ll be faithful. By the power of the Spirit, our simple, childlike faith as converts is transformed into mature faithfulness. As Paul says in Romans, it’s from faith to faith.
(Rom. 1:17 NET) For the righteousness of God is revealed in the gospel from faith to faith, just as it is written, “The righteous by faith will live.”
So back to where we began —
(1 Thess. 5:23-24 ESV) 23 Now may the God of peace himself sanctify you completely, and may your whole spirit and soul and body be kept blameless at the coming of our Lord Jesus Christ. 24 He who calls you is faithful; he will surely do it.
How are we sanctified completely (v. 23)? The God of peace himself will do this. How? Through his Spirit.
Will we in fact be perfectly sinless? Not in this life. But will God transform us to be faithful? Of course. God’s goal is that we be saved, so much so that he’s willing to give a part of himself — the Spirit — to dwell within us to change our hearts so that we’ll be incrementally changed to emulate the faithfulness of Jesus — and so make it to the end.