There is an antagonism between God’s people and the world which cannot be removed and which Christians should not try to remove. It is put in place by the Lord and exists because of the different natures he has given us.
The temptation for some is to try to find a neutral no-man’s land between opposing worldviews in order to enter into dialogue. This is both unworkable and wrong. The Christian’s strongest defence is the whole of God’s truth, and he is told to put on the full armour of God. He cannot give up certain of his fundamental beliefs in order to try to communicate with the world. He cannot fall back to arguing from pure reason to establish his presuppositions, when he is supposed to start with faith in Scripture and to advance with his belief in all of God’s truth intact. This is his strongest position. He is not to argue lost men and women into the kingdom by intellectual arguments alone, but to preach the authoritative gospel to them and to address man’s conscience, so that the Holy Spirit brings them under conviction of sin.
There must be separation between Christians and the world which they have been called out of. They belong to Christ and Christ hates the world as a system, and will never change his opposition to it. The believer’s antagonism to the world reflects Christ own unchanging attitude. ‘What concord hath Christ and Belial?’ At the same time the believer is to try to win the lost, but never by going back into the world or returning to what he was before. He is to keep up his loathing for sin, first in himself and then as found in all the attitudes and philosophies of the world. He is to accept the reality of God’s forgiveness by distinguishing between sin and the sinner, for by the grace of God the sinner can be extracted from his sin.