IT seems rather the fashion, just now, to deny the existence of Satan as a person at all. I suppose nothing could please him more than to be so denied. "I don't believe in a personal devil," said a lady in a Bible class; "I believe in a principle of evil." When asked to define what she meant by a principle of evil, it appeared that she had no very clear idea of the matter herself. The simple truth is that there is as much proof of the personality of Satan as of the Holy Spirit, and a believer in the Bible may as reasonably deny one as the other. Our Lord always speaks of him as a living, thinking, active being, as in St. John viii. 44, St. Matt. xiii. 19 and 39, and many other places. Try substituting the words "principle of evil" in these passages, and see what sense it will make. Satan is perhaps the most active member of that famous old firm "the world, the flesh, and the devil," in which indeed there are no silent partners. He is always ready to back the others, and, what is still worse, he has a secret ally in every heart, who, though crushed and kept under, is always trying to open correspondence with its old friend. He does not come to us in hideous disguise of hoof and horn, as the old painters have depicted him. None but a fool would do that; and he is no fool as concerns the ends he would compass. "The devil knows many things," says the Arab proverb, "because he is very old." He knows how to put on many disguises, and can on occasions transform himself into an angel of light. Pride and anger, envy, hatred, and malice, are usually the sins specially attributed to Satan; but there is one class of sins which are particularly his own. I refer to lying in all its branches, to evil-speaking, slander, detraction, and the like. "When he speaketh of a lie, he speaketh of his own, for he is a liar, and the father of it," says our Lord. (St. John viii. 44.) Slander is his business and delight. He is "the accuser of our brethren" (Rev. xii. 10), and the patron of them that do the like.