Below I have a quote from A.W.Pink. He was required reading for me in the Bible school I went to, a four point Calvinist school. I am not a Calvinist and therefore much of Pink’s teachings I would not endorse. Yet he and I have come to very similar conclusions as it relates to churches. Here is the quote……………

“Be ye not unequally yoked together.” This applies first to our religious or ecclesiastical connections. How many Christians are members of so-called “churches,” where much is going on which they know is at direct variance with the Word of God either the teaching from the pulpit, the worldly attractions used to draw the ungodly, and the worldly methods employed to finance it or the constant receiving into its membership of those who give no evidence of having been born again. Believers in Christ who remain in such “churches” (?) are dishonoring their Lord. Should they answer: “Practically all the churches are the same, and were we to resign, what could we do? We must go somewhere on Sundays,” such language would show they are putting their own interests before the glory of Christ. Better stay at home and read God’s Word, than fellowship that which His Word condemns.”

Pink’s first point for me is a vital one. He says of “Be ye not unequally yoked together,” that it applies first to our religious or ecclesiastical connections. I would agree with that. When you mention that Scripture people automatically assume one is speaking of marriage. And while it is true that one should not be unequally yoked, meaning a believer should not marry a believer, this is not what the context of that particular Scripture is alluding to. Read 2 Cor 6:14-16 and see that it has nothing to do with marriage. And then read the conclusion of what Paul has just written for the confirmation. “Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you, And will be a Father unto you, and ye shall be my sons and daughters, saith the Lord Almighty.
(2Co 6:17-18)

Come out from among them. That is the wherefore. The word wherefore is an old one. It means in essence “For that reason.” So Paul is saying that because of what he has just stated about being unequally yoked, for that reason come out from among them. This is where I am and have been for a number of years. I have come out from among them lest I be unequally yoked. I have very carefully chosen with whom to fellowship with over the last ten years or so and it has transformed my walk into something much deeper. There is a cost of course, a price to be paid for following the literal teachings of the New Testament. Yet to me, this is who the remnant are. A people willing to pay the price, whatever it is, to follow Jesus and His Word and the leading of the Holy Spirit.