J. Gresham Machen…
The field of Christianity is the world. The Christian cannot be satisfied so long as any human activity is either opposed to Christianity or out of all connection with Christianity.
Christianity must pervade not merely all nations, but also all human thought. The Christian, therefore, cannot be indifferent to any branch of earnest human endeavor.
It must all be brought into some relation to the gospel. It must be studied either in order to be demonstrated as false, or else in order to be made useful in advancing the Kingdom of God. The Kingdom must be advanced not merely extensively, but also intensively. The Church must seek to conquer not merely every man for Christ, but also the whole of man.”