Jehu did not kill all of these people personally, rather he commanded for them to be killed. Alternate translation: "So Jehu commanded for all ... to be killed" or "So Jehu commanded for all ... to die" (See: [[rc://en/ta/man/translate/figs-metonymy]])
This means that they had all been killed. Alternate translation: "until all of them had been killed" or "until all of them were dead" (See: [[rc://en/ta/man/translate/figs-euphemism]])