"?If it be true, as St. Paul says, that followers of the Lord Jesus are engaged in a lifelong struggle "against the rulers of the darkness of this world, against spiritual wickedness in high places," it is obviously necessary that they should be able to recognise their spiritual adversaries, and to understand the methods which those adversaries employ to undermine the Christian faith. When His disciples questioned our Lord concerning the events which would precede His Second Advent, He spoke of doctrines which, although formulated by devils, would be so plausible as to deceive the very elect, if that were possible. We should, therefore, be on our guard, not only against those doctrines which are openly anti-Christian, but also against those subtler and more seductive doctrines which masquerade under the guise of Christianity itself."