Two antagonists are at hand-grips in every one of us. On the one hand, the 'God of peace,' on the other, 'Satan.' If you believe in the personality of the One, do not part with the belief in the personality of the other. If you believe that a divine power and Spirit is ready to help and strengthen you, do not think so lightly of the enemies that are arrayed against you as to falter in the belief that there _is_ a great personal Power, rooted in evil, who is warring against each of us. Ah, brethren! we live far too much on the surface, and we neither go down deep enough to the dark source of the Evil, nor rise high enough to the radiant Fountain of the Good. It is a shallow life that strikes that antagonism of God and Satan out of itself. And though the belief in a personal tempter has got to be very unfashionable nowadays, I am going to venture to say that you may measure accurately the vitality and depth of a man's religion by the emphasis with which he grasps the thought of that great antagonism. There is a star of light, and there is a star of darkness; and they revolve, as it were, round one centre. But whilst, on the one hand, our Christianity is made shallow in proportion as we ignore this solemn reality, on the other hand, it is sometimes paralysed and perverted by our misunderstanding of it. For, notice, 'the God of peace shall bruise Satan _under your feet_.' Yes, it is God that bruises, but He uses our feet to do it. It is God from whom the power comes, but the power works through us, and we are neither merely the field, nor merely the prize, of the conflict between these two, but we ourselves have to put all our pith into the task of keeping down the flat, speckled head that has the poison gland in it. 'The God of peace'--blessed be His Name--'shall bruise Satan under your feet,' but it will need the tension of your muscles, and the downward force of your heel, if the wriggling reptile is to be kept under.