1 Thessalonians 4:3–5

God's will: live apart from sexual immorality, with honor

3For this is the will of God, your sanctification: that you abstain from sexual immorality;

4that each of you know how to possess his own vessel in sanctification and honor,

5not in the passion of desire, as also the nations do who do not know God;

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In its context

1Finally, then, brothers, we ask you and exhort you in the Lord Jesus, that, just as you received from us how you ought to walk and to please God —just as you indeed are walking— that you abound more and more.

2For you know what instructions we gave you through the Lord Jesus.

…

6that no one transgress and take advantage of his brother in this matter, because the Lord is an avenger concerning all these things, as we also told you before and solemnly testified.

7For God did not call us to impurity but in sanctification.

Read all of 1 Thessalonians 4

Its words in the original

Purity