Neither repented they of their murders, nor of their sorceries, nor of their fornication, nor of their thefts.

People's New Testament

9:21 Neither repented they of their murders. In the Crusade against the Albigenses, conducted by Rome in the thirteenth century, it is estimated that one million martyrs perished.

Nor of their sorceries. Tricks to deceive, so characteristic of the priests.

Nor of their fornications. This term may mean spiritual fornication or apostasy, and it may mean literal fornication. In either sense it is true of the religious features of the fifteenth century.

Nor of their thefts. Thefts in resorting to deceptions and impostures to extort money from the people. Tetzel's mission to Germany early in the sixteenth century is an illustration. Instead of repentance after the great judgment on the Eastern Church, the Western Church grew worse and worse.

Jamieson-Fausset-Brown Bible Commentary

21. sorceries-witchcrafts by means of drugs (so the Greek). One of the fruits of the unrenewed flesh: the sin of the heathen: about to be repeated by apostate Christians in the last days, Re 22:15, "sorcerers." The heathen who shall have rejected the proffered Gospel and clung to their fleshly lusts, and apostate Christians who shall have relapsed into the same shall share the same terrible judgments. The worship of images was established in the East in A.D. 842.

fornication-singular: whereas the other sins are in the plural. Other sins are perpetrated at intervals: those lacking purity of heart indulge in one perpetual fornication [Bengel].

Matthew Henry's Concise Commentary

9:13-21 The sixth angel sounded, and here the power of the Turks seems the subject. Their time is limited. They not only slew in war, but brought a poisonous and ruinous religion. The antichristian generation repented not under these dreadful judgments. From this sixth trumpet learn that God can make one enemy of the church a scourge and a plague to another. The idolatry in the remains of the eastern church and elsewhere, and the sins of professed Christians, render this prophecy and its fulfilment more wonderful. And the attentive reader of Scripture and history, may find his faith and hope strengthened by events, which in other respects fill his heart with anguish and his eyes with tears, while he sees that men who escape these plagues, repent not of their evil works, but go on with idolatries, wickedness, and cruelty, till wrath comes upon them to the utmost.