These verses give background information telling us what Saul has been doing since the stoning of Stephen. Here the word "him" refers to the high priest and "he" refers to Saul. (See: [[rc://en/ta/man/translate/writing-background]])
The noun "murder" can be translated as a verb. Alternate translation: "still speaking threats, even to murder the disciples" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])