4 Ye adulterers. I connect this verse with the foregoing verses: for he calls them adulterers, as I think, metaphorically; for they corrupted themselves with the vanities of this world, and alienated themselves from God; as though he had said, that they had become degenerated, or were become bastards. We know how frequent, in Holy Scripture, is that marriage mentioned which God forms with us. He would have us, then, to be like a chaste virgin, as Paul says, (2 Corinthians 11:2.) This chastity is violated and corrupted by all impure affections towards the world. James, then, does not without reason compare the love of the world to adultery.
They, then, who take his words literally, do not sufficiently observe the context: for he goes on still to speak against the lusts of men, which lead away those entangled with the world from God, as it follows, —
The friendship of the world. He calls it the friendship of the world when men surrender themselves to the corruptions of the world, and become slaves to them. For such and so great is the disagreement between the world and God, that as much as any one inclines to the world, so much he alienates himself from God. Hence the Scripture bids us often to renounce the world, if we wish to serve God.