Jamieson, Fausset and Brown on Revelation 22:11

11. unjust--"unrighteous"; in relation to one's fellow men; opposed to "righteous," or "just" (as the Greek may be translated) below. More literally, "he that doeth unjustly, let him do unjustly still."

filthy--in relation to one's own soul as unclean before God; opposed to holy," consecrated to God as pure. A omits the clause, "He which is filthy let him be filthy still." But B supports it. In the letter of the Vienne and Lyons Martyrs (in Eusebius) in the second century, the reading is, "He that is lawless (Greek, 'anomos') let him be lawless; and he that is righteous let him be righteous (literally, 'be justified') still." No manuscript is so old. A, B, Vulgate, Syriac, Coptic, Andreas, and Cyprian read, "let him do righteousness" (1Jo 2:29; 3:7). The punishment of sin is sin, the reward of holiness is holiness. Eternal punishment is not so much an arbitrary law, as a result necessarily following in the very nature of things, as the fruit results from the bud. No worse punishment can God lay on ungodly men than to give them up to themselves. The solemn lesson derivable from this verse is, Be converted now in the short time left (Re 22:10, end) before "I come" (Re 22:7, 12), or else you must remain unconverted for ever; sin in the eternal world will be left to its own natural consequences; holiness in germ will there develop itself into perfect holiness, which is happiness.