In the sermons he delivered on the Ten Commandments as early as 1516 and 1517, and which, in 1518, he published in book form,[1145] he took over an abundance of superstition from the beliefs current amongst the people, and from such writers as Geiler. In 1518 and 1519 were published no less than five editions in Latin of the sermons on the Decalogue; the book was frequently reprinted separately and soon made its appearance in Latin in some collections of Luther’s writings; later on it figures in the complete Latin editions of his works; six German editions of it had appeared up to 1520 and it is also comprised in the German collections of his works. In his old age, when the “evils of sorcery seemed to be gaining ground anew,” he deemed it “necessary,” as he said,[1146] “to bring out the book once more with his own hand”; certain tales, amongst which he instances one concerning the devil’s cats and a young man, might serve to demonstrate “the power and malice of Satan” to all the world. One cannot but regard it as a mistake on Luther’s part, when, in his sermons on the Ten Commandments, he takes his hearers and readers into the details of the magic and work of the witches, though at the same time emphasising very strongly the unlawfulness of holding any communication with Satan. This stricture tells, however, as much against many a Catholic writer of that day. It is in his commentary on the 1st Commandment that he gives us a first glimpse into the world of witches which later was to engross his attention even more. He is anxious to bring home to the “weaklings” how one can sin against the 1st Commandment.[1147] He therefore enumerates all the darkest deeds of human superstition; of their reality he was firmly convinced, and only seldom does he speak merely of their “possibility,” or say, “it is believed” that this or that took place. He also divides into groups the people who sin against the virtue of Divine love, doing so according to their age, and somewhat on the lines of a Catechism, in order that “the facts may be more easily borne in mind.” “The third group,” he says, “is that of the old women, etc.” “By their magic they are able to bring on blindness, cause sickness, kill, etc.”[1148] “Some of them have their fireside devil who comes several times a day.” “There are _incubi_ and _succubi_ amongst the devils,” who commit lewdness with witches and others. Devil-strumpetry and ordinary harlotry are amongst the sins of these women. Luther also speaks of magic potions, desecration of the sacrament in the devil’s honour, and secret incantations productive of the most marvellous effects.