(1) The moral demand is first put in the negative form: "Be not unequally yoked with unbelievers." The peculiar word ἑτεροζυγοῦντες ("unequally yoked") has a cognate form in Lev. xix. 19, in the law which forbids the breeding of hybrid animals. God has established a good physical order in the world, and it is not to be confounded and disfigured by the mixing of species. It is that law (or perhaps another form of it in Deut. xxii. 10, forbidding an Israelite to plough with an ox and an ass under the same yoke) that is applied in an ethical sense in this passage. There is a wholesome moral order in the world also, and it is not to be confused by the association of its different kinds. The common application of this text to the marriage of Christians and non-Christians is legitimate, but too narrow. The text prohibits every kind of union in which the separate character and interest of the Christian lose anything of their distinctiveness and integrity. This is brought out more strongly in the free quotation from Isa. lii. 11 in ver. 17: "Come out from among them, and be separate, saith the Lord, and touch not anything unclean." These words were originally addressed to the priests who, on the redemption of Israel from Babylon, were to carry the sacred temple vessels back to Jerusalem. But we must remember that, though they are Old Testament words, they are quoted by a New Testament writer, who inevitably puts his own meaning into them. "The unclean thing" which no Christian is to touch is not to be taken in a precise Levitical sense; it covers, and I have no doubt was intended by the writer to cover, all that it suggests to any simple Christian mind now. We are to have no compromising connexion with anything in the world which is alien to God. Let us be as loving and conciliatory as we please, but as long as the world is what it is, the Christian life can only maintain itself in it in an attitude of protest. There always will be things and people to whom the Christian has to say No!