" Though the redemption purchased by Christ, as described in this epistle, is so complete and so free, yet between the beginning and the consummation of the work there is a protracted conflict. This is not a figure of speech. It is something real and arduous. Salvation, however gratuitous, is not to be obtained without great effort. The Christian conflict is not only real, it is difficult and dangerous. It is one in which true believers are often grievously wounded; and multitudes of reputed believers entirely succumb. It is one also in which great mistakes are often committed and serious loss incurred from ignorance of its nature, and of the appropriate means for carrying it on. Men are apt to regard it as a mere moral conflict between reason and conscience on the one side, and evil passions on the other. They therefore rely on their own strength, and upon the resources of nature for success. Against these mistakes the apostle warns his readers. He teaches that every thing pertaining to it is supernatural. The source of strength is not in nature. The conflict is not between the good and bad principles of our nature. He shows that we belong to a spiritual, as well as to a natural world, and are engaged in a combat in which the higher powers of the universe are involved; and that this conflict, on the issue of which our salvation depends, is not to be carried on with straws picked up by the wayside. As we have superhuman enemies to contend with, we need not only superhuman strength, but divine armour and arms. The weapons "
― Charles Hodge , Ephesians