2 Corinthians 6:18

and will be a Father unto you, and ye shall be My sons and daughters, saith the Lord Almighty.

The enthusiasm of the inspired writer has carried him forward to a wonderful height of eloquence in picturing true faithfulness in the ministry of the Gospel. Before making the application of the appeal of v. 1 to the various relations of life, therefore, the apostle here pours forth some of the affectionate feeling which he cannot hide from them: Our mouth is open to you, O Corinthians; our heart is enlarged. He feels constrained to speak openly and without reserve to them; for it is his love which causes him to speak with such plain candor and frankness, which will not suffer him to remain silent, but urges him to show such confidence toward them. A similar thought is contained in the thought of the enlargement of his heart in their behalf, for the expression indicates the widening of his sympathy for them. In speaking to them so frankly, Paul had really become aware of the depth and extent of his affection for them.

This fact being so, the other thought follows: You are not straitened in us, but you are straitened in your own affections; you have no small room in us, but you have very little room for us in yourselves. The apostle's heart was enlarged in love for them, it widened out in sympathy and love for them and encompassed them all, but they, on their part, did not feel an equal love and sympathy for the apostle. He was not a man of narrow sympathies, as his opponents may have suggested, but the lack of sympathy was all on their side. And yet, he had a right to expect that: But as a retribution, a recompense, of the same kind (I speak as to my children) be enlarged also you. Because children are bound to make a return of love for a father's lore, because they should feel obliged to pay back the same amount of love that they have received, therefore he calls upon them to be enlarged in heart, to exhibit a wider affectionate sympathy toward him. That he expected.

That his admonition is intended only with reference to himself and to his work and does not apply to the undue tolerance which would permit the worship of false gods, the apostle now brings out in a passage replete with brilliancy: Be not united incongruously with unbelievers. That is the thesis, the topic, of the entire passage. If they should be yoked together with unbelievers, it would be an unequal yoking together. The apostle has in mind the provision of the Jewish ceremonial law according to which the yoking together of clean and unclean animals was prohibited, Deuteronomy 22:10. If the believers, the members of the Christian community, should in any way join with the heathen in their idol worship, if they should associate with them in such a way as to erase the essential difference between Christian and heathen, then this union would be absurd and wicked, with the peril of leading to denial attached, and should therefore not be practiced by the Christians.

The apostle enforces his thought by illustrating the incongruity between Christianity and heathendom in five contrasts. He asks: For what communion, what fellowship, is there to righteousness and lawlessness? What have they in common? On the one hand, there is the active disposition to live in accordance with the divine will; on the other hand, there is no knowledge of the divine, sanctifying will, and therefore nothing but unrighteousness. Obviously, then, there can be no participation between the two; they are contrasts. Or what communion has light with darkness? On the one side is light and salvation, with God; on the other is darkness and destruction, with Satan; the two can never unite without destroying their substance.

A third question, contrasting the Son of God with the adversary of Himself and of all mankind: But what is Christ's concord toward Belial? How can there ever be an agreement between Christ, the Champion of that which is right and good, which is intended for man's salvation, and the chief of Christ's adversaries? The personification of righteousness and perfection against the personification of unrighteousness and lawlessness that abyss can never be bridged. The last two questions concern the contrast between those that are saved and those that are destroyed: Or what portion is to the believer with the unbeliever? But what agreement is to the temple of God with idols? The Christian, the one that has faith in Christ, can have no part with such as are heathen, as have no faith. Their character, their possessions, their interests, differ so totally and utterly that a combination of the two contrasted parties cannot be imagined. And equally absurd is the idea that the temple of God should have anything in common with idols. One might just as soon think of setting up idols in the sanctuary of God as to have those that have been consecrated to the Lord join with the heathen in any part of their false worship.

For the sake of emphasizing the entire passage, the apostle explains his last comparison: For we are the temple of a God that is living. Any agreement with the worship of dead and powerless idols, no matter in what form, is therefore out of the question. And that Paul is right in representing the body of the true believers as a temple of God he proves from a passage of the Old Testament, which he quotes in a free translation: I will dwell in them and walk in them, and I will be their God, and they shall be My people, Leviticus 26:11. The believers are a habitation of God through the Spirit, Ephesians 2:22. God Himself, the Triune Godhead, has made His abode in them, John 14:23. See Ezekiel 37:26; Hosea 2:23; Jeremiah 24:7. God lives in the midst of His congregation in the Word and in the Sacraments; His Word is effective in them through the ministry of the Word, in effecting faith and a holy life. The believers have no thought for, no interest in, any other God but the one that dwells in them, and He that made them His people is pleased to continue as their God.

From this relation, however, it follows what Paul adds in the form of a peremptory command of the Lord: Wherefore, come out from the midst of them and separate yourselves, says the Lord, and touch not an unclean thing. Paul here, as Luther says, melts together many verses into one heap, and casts such a text there from as gives the meaning of the entire Scriptures. The thought is that of Isaiah 52:11, where the deliverance of the Israelites from Babylon is pictured as a redemption. The mere touching of the unclean thing will make the believer a partaker of strange uncleanness and a denier of the Lord. "The admonition here is that they should come out in the most decided manner from the whole sphere of heathenish worldly life, should separate themselves in spirit from their heathen neighbors, should avoid all heathenish practices which might defile men consecrated to God, and especially abstain from all idolatrous festivals."

The result of this uncompromising attitude on the part of the believers is finally stated, also in a combination of Scripture-passages from the Old Testament: And I will receive you, and I will be to you a Father, and you shall be to Me sons and daughters, says the Lord Almighty. See Exodus 4:22; Jeremiah 31:9; Hosea 1:10; Isaiah 43:6. The promise of God, contained in all parts of His holy Word, is not only that His grace will make the believers an assembly dedicated to Him, but he promises them the position of sons and daughters, together with the heritage of heaven, Galatians 4:4. And there can be no doubt as to His ability to make good His promise of adding us to His household and giving us all the blessings of true children, because He is the Lord, the almighty Governor of all things, 2 Samuel 7:8. Note: The manner in which the apostle quotes the Old Testament is entirely in line with his own inspired character. "The concluding verses of this chapter are an instructive illustration of the way in which the New Testament writers quote the Old.
1. They often quote a translation which does not strictly adhere to the original.
2. They often quote according to the sense, and not according to the letter.
3. They often blend together different passages of Scripture, so as to give the sense, not of any one passage, but the combined sense of several.
4. They sometimes give the sense, not of any particular passage or passages, but, so to speak, the general sense of Scripture. There is no such passage in the Old Testament, for example, as that contained in this last verse, but the sentiment is often and clearly expressed.
5. They never quote as of authority any but the canonical books of the Old Testament. " (Hodge.)

Mark also: The language of Paul in this entire section is held in such a majestic strain and, at the same time, shows his command of the Greek language in such a clear way that it is rightly regarded as one of the finest in all his letters. And finally: This passage is properly applied in the case of false union with sectarian churches. For inasmuch and in so far as any church-body has the unclean thing in its midst in the form of any false doctrine or anti-scriptural practice, insomuch and in so far it is contaminated and may become contaminating. If even that is a contamination for believers to be united with unbelievers in matters which further the idolatrous ideas of the latter, much more is the unionism of the present day to be condemned, which ignores differences of creed and practice with the specious plea that the Church must be a power in the world. It is only by retaining both doctrine and life in the greatest possible, in absolute, purity that the Church will be able to fulfill its mission of being a salt in the world. But if the salt have lost its savor, wherewith shall it be salted? Mark 9:50.

Summary

Paul shows that he and his fellow-ministers do the work of their office in the midst of all the difficulties besetting them; he appeals to the believers to avoid all fellowship with the unbelievers and their practices.