Jamieson, Fausset and Brown on 1 Kings 21:17-19

17-19. Hast thou killed, and also taken possession?--While Ahab was in the act of surveying his ill-gotten possession, Elijah, by divine commission, stood before him. The appearance of the prophet, at such a time, was ominous of evil, but his language was much more so (compare Eze 45:8; 46:16-18). Instead of shrinking with horror from the atrocious crime, Ahab eagerly hastened to his newly acquired property.