The Corinthians were not only straitened in their affections. They were lax in their associations. Had Christ been the object, the new life had not been hindered in either way; for as He creates, directs, and sustains the affections according to God, so does He guide and guard the feet in the narrow way, His own path outside and above the world. Where He is not before the heart, the world in one form or another fails not to ensnare, fair excuses which cover unholy alliances escape detection, and His honor somehow is ere long compromised.
The apostle's jealousy was alive to this danger in a love that bound together Christ and the church. Love speaks and acts freely, though with tender consideration. The apostle comprehends in his wide warning not only idolatry, but every kind of worldly association as defiling and unworthy of the Christian, because it suits not Christ nor the presence of God. If blessed with Christ for eternity, you cannot without sin have relations with the enemy in time.
Some have narrowed, if not perverted, the passage, by restricting it to an exhortation against the marriage of a believer with an unbeliever. But while the principle undoubtedly condemns the contracting of any such union, it is clear on the face of it that, strictly speaking, this cannot be the direct intent; for the corrective insisted on is exactly what one ought not to follow, even in so sad a case. Thus a Christian woman who had sinned in marrying a worldly man ought not to come out or be separate from her husband; and she might expect the strongest censure from God and His children, not promised blessing, were she to act thus rashly, whatever the purity of her motives. In fact, 1 Cor. 7 is the true and direct weapon for the question of marriage; our passage has a far larger bearing. It is the prohibition of every evil connection for a Christian, and it calls for thorough clearance from all; and no wonder, since the Christian has Christ for his life, righteousness, and hope, even now by the Spirit able to behold His glory without veil. It is incongruous, it is treason, if one has taken Christ's yoke, to accept also that of the world which rejected and crucified Him.
“Be not diversely yoked with unbelievers; for what partnership [is there] for righteousness and lawlessness? or what fellowship [hath] light with darkness? and what consent of Christ with Beliar? or what part for a believer with an unbeliever? and what agreement for God's temple with idols? for ye are [the] living God's temple, even as God said, I will dwell and walk among them, and will be their God, and they shall be my people.” (Vers. 14-16.)
The figure with which the paragraph opens is obviously taken from the law which forbade yoking together heterogeneous animals, as the ox and the ass in plowing. (Deut. 22: 10.) It is not now the Jew severed from the Gentile, but the Christian separate from the world in every shape and degree. Principles, motives, interests, ways, are not only different but opposed; what common ground is possible? But this is not all. Faith is the life-breath of the Christian, and his only-avowed power the Holy Ghost, whom the world cannot receive as neither seeing nor knowing Him; and He works to reduce every thought to the obedience of Christ in absolute judgment of the world and its prince.
In detail what can be stronger than the clenching blows of every clause? First the apostle points to the radical difference of principles, low or high, righteousness and lawlessness, light and darkness. Next he points to their characteristic heads, Christ and Beliar. Then he contrasts the partisans or followers, believers and unbelievers. Lastly he closes with their joint place as God's temple, contrasted with idols. Thus all that forms the life outward and inward is embraced so as to exclude alliance with the world and claim the saints wholly for Christ apart from the world. This in no way bars doing good to all, or especially seeking the salvation of any. On the contrary, the truer the separateness to Christ, the more forcibly can grace be preached to the world as a lost thing, and Christ the only Savior. For righteousness was even looked for in a saint; light, now that Christ was revealed, is characteristic of a Christian.