1 Thessalonians 4:8

He, therefore, that despiseth, despiseth not man, but God, who hath also given unto us His Holy Spirit.

The apostle here points to a second vice, one which is often mentioned together with uncleanness, See Ephesians 4:19; Ephesians 5:3; Colossians 3:5, that of avarice, of greed: That no one overreach and defraud his brother in business, because that the Lord is an avenger concerning all these things, as we have said to you before and testified. The description given in these words fitly characterizes the sin of covetousness; for the greedy person goes beyond the limits set by the Law of God; he resorts to trickery and cheating. This will invariably result in fraud, in the deliberate attempt to get the better of every deal, to enrich oneself at the expense of one's neighbor. Undoubtedly this vice was common in the great Aegean seaport and was not regarded as anything reprehensible, just as the average businessman in our day deems it an evidence of extraordinary astuteness if he can indulge in profiteering without being detected. But the apostle holds up a warning finger, saying that the Lord is an avenger with respect to all these things. The sin may not become manifest before the eyes of men, but before the eyes of God nothing is hidden, and His punishment will strike the wicked in due time. The Christians being subject to the same sinful desires as all other men by reason of their evil flesh, Paul had included this warning in his instructions to the Thessalonians; he had, before, in an earnest testimony, told them the same thing,

With reference to both vices he therefore adds: For not has God called us for uncleanness, but in sanctification. The holy God wants clean hearts; to that end and object He called the believers, working faith and love in their hearts by His call. A Christian cannot live in any form of uncleanness with regard to any of the commandments; if that had been God's purpose in calling him, He would become a servant of sin. The apostle, therefore, extends his warning: Wherefore, then, he that despises does not despise man, but God, who gave His Holy Spirit to you, To disregard the precept and warning which Paul here issues does not mean a mere despising of men. That in itself may be bad enough, but could at least be condoned. No, it is God's will which the apostle has proclaimed with regard to these sins, and every one that despises his instructions thereby becomes guilty of despising God. Such a person is all the more culpable in the sight of God because the Lord, in issuing the call, in working conversion, gave His Holy Spirit, thereby granting the power to walk in newness of life. Any person that has once been converted and then deliberately indulges in such sins as here mentioned by the apostle, drives the Holy Spirit out of his heart and thus receives to himself damnation, unless he repents of his sin before it is too late. This fact cannot be emphasized too strongly in our days when indifference and worldliness is raising its head in the midst of the Christian Church.