When the Bible calls God ‘holy’ it means He is ‘other than’ or totally unlike humans, set apart from us in all ways. Even though we are made in His image and are to reflect His likeness, we fall short of His glory because of our sin.
‘Sanctification’ is a term meaning ‘set apart’ for God. It is like designating a china bowl only for one use; it cannot be used for any other purpose. God sanctifies those who put their faith in Christ, and for the rest of our lives, He perfects that sanctification.
Holiness and sanctification come from the same Greek root word. Its usage shows that God’s desire for me is to be like Him and be ‘other than’ I once was and ‘other than’ those who do not know or believe in Him. While the Bible clearly shows this is His desire for all that I am and all that I do, many passages focus on some of the major issues. This is one of them . . .
Finally, then, brothers, we ask and urge you in the Lord Jesus, that as you received from us how you ought to walk and to please God, just as you are doing, that you do so more and more. For you know what instructions we gave you through the Lord Jesus. For this is the will of God, your sanctification: that you abstain from sexual immorality; that each one of you know how to control his own body in holiness and honor, not in the passion of lust like the Gentiles who do not know God; that no one transgress and wrong his brother in this matter, because the Lord is an avenger in all these things, as we told you beforehand and solemnly warned you. For God has not called us for impurity, but in holiness. Therefore whoever disregards this, disregards not man but God, who gives his Holy Spirit to you. (1 Thessalonians 4:1–8)
I notice the words “just as you are doing” and “that you do so more and more.” Christians are set apart for God, yet being restored to what God intended in creation is a process. He encourages what I’ve learned and obeyed thus far, but we are not to stop growing and changing.
One big area of human life is our sexuality. God’s Word clearly describes what this means for us, and contrasts it here with what it does not mean. I’m not to be controlled by passion and lust like those who do not know God. Living like them exploits and manipulates people and God will avenge those who become impure in this way. Sexual immorality not only disregards others, but disregards God.
The last phrase shows how doing what unbelievers do is a rejection of God. He “gives his Holy Spirit to you.” The Spirit of God is holy, unlike any other spirit, set apart to serve the glory of God and has been given to God’s people so we can be like Him.
I cannot think of any deep illustrations for the seriousness of this, only trivial examples such as: this is like driving an old rusty and worn-out car when I have a Lamborghini Veneno sitting in the garage, filled with gas, and ready to go. Living by my own strength is bad enough, but when offered the strength of Almighty God to live a ‘set apart’ life only to refuse it so I can go on a joy ride in a junk heap is more than a slap in God’s face; it is irrational and totally foolish.
Making that choice not only hurts others and harms me, it rejects with contempt the only One who loves me with an everlasting love and sacrificed His own life that I might forever live a holy and sanctified life with Him in eternity.
This passage is about one kind of sin, but it is true of everything that is contrary to holiness. No matter what I do, God has set me apart for His own — and I’m to live that way!