If there is one theme at the end of chapter 3 and the start of chapter 4 (which is why it was probably a bad idea to break this section up with the chapter division), it’s holiness.
Time and again, we see words with the same Greek root meaning “holiness”, which unfortunately is not so clear in the English.
Holiness, of course, often has a duel meaning. One is “purity” and the other is “set apart,” which in the case of the Christian, means “set apart for God as his own special people.”
And in this passage, Paul prays that God would make the Thessalonians and all the “saints” blameless in “holiness” before our God.” (3:13)
Many times we thinks of saints as the super spiritual, but “saint” shares the same root word as “holiness” just a few words earlier in the verse. All Christians are saints, because we are all set apart for God as his own special people. And because of that we are to live lives that are blameless and pure.
Paul stresses that a few sentences later, saying,
For this is God’s will, your sanctification…(4:3)
Again, “sanctification” has that same root as the words “holiness” and “saints.” God’s will for us is that we live lives that are set apart for him, lives that are pure.
Paul specifically tells us to be pure sexually, which was as big a problem back then as it is now. And he emphasizes,
For God has not called us to impurity but to live in holiness. (4:7)
And then he says,
Consequently, anyone who rejects this does not reject man, but God, who gives you his Holy Spirit. (4:8)
Some people who claim to be Christians try to do just that: they reject God’s call on their lives to be holy. They would much rather live in their lusts. But in doing so, they’re actually rejecting God. Can you really call such a person a Christian if that’s how they live the entirety of their lives?
We are called to be holy, because he is holy. And his Holy (there’s that word again) Spirit is living in us. If the the Spirit, who himself is holy, is truly living in us, how can we then live unholy lives, never repenting, but always making excuses and justifying our actions?
So let us listen to the Spirit in our lives. Let us follow his leading each day. Let us live by his power each day. We will never be able to live holy lives in our own strength, by our own willpower. But the Spirit works us in us daily, and as we listen to him, we become more and more like the One who loved us and gave his life for us. And ultimately, isn’t that our hope.
So as we strive for holiness, let us not only remember Paul’s words, but John’s, who wrote,
See what kind of love the Father has given to us, that we should be called children of God; and so we are. The reason why the world does not know us is that it did not know him. Beloved, we are God’s children now, and what we will be has not yet appeared; but we know that when he appears we shall be like him, because we shall see him as he is. And everyone who thus hopes in him purifies himself as he is pure. (1 John 3:1-3)