Matthew Poole and continuators on 1 Thessalonians 4:3

3 For this is the will of God , even your sanctification that ye should abstain from fornication .

What in the former verse he called commandment from Christ, he here calls the Will of God. Or he had some further duties to lay before them, which he had not yet given commandments about, which were the Will of God. There is the secret and revealed Will of God, and his revealed Will is about things to be beleived or practised. The latter is here meant so that the Will of God is put figuratively here for the things he willeth, or commandeth of us.

And that which the Apostle first mentions is Sanctification, which is often taken for holiness in general, which consists in mens conformity to the will of God both in the heart and life.

But I think not so taken here, but for chastity, as opposite to the sin of uncleanness, as the Apostle explains it in the next words. For to abstain from Fornication is the Will of God. And by it is meant all unchastness either of persons married, or unmarried. And that either in the heart, or in speech, or in the eye, or lascivious gesture as well as in the veryact it self. It was a sin common among the Gentiles, especially the Grecians, and judged as no sin. And therefore it is particularly mentioned and forbidden to the believing Gentiles by the Council of Ierusalem, least they should apprehend it not to be an evil, Act. 15.20. For it is not so evident by the light of nature as many other moral evils, and therefore the Apostle tells the Thessalonians that it is the Will of God they should abstain from it, and that is a sufficient ground either of doing, or not doing: This Will of God is exprest in the seventh Commandment, which though the Jews well knew, yet these new converted Gentiles might not yet so well understand. And therefore the Apostle in his several Epistles to the Gentile Churches doth dehort them from it, especially the Corinthians, 1 Cor. 6.9. and that by many arguments. It is a sin which corrupts and effeminates the mind, captivates the heart, consumes the Flesh, and wasts mens Estates. So that this will of God that forbids it is a good will, Rom. 12.2. as all the Commandments of God are said to be for our good, Deuteronomy 10.13.