Here "set himself" is a metaphor for being determined to do something. Seeking God represents choosing to know, worship, and obey him. Alternate translation: "He was determined to obey God" (See: [[rc://en/ta/man/jit/figs-metaphor]])
Here "the days of Zechariah" is a metonym referring to the time period during which Zechariah was priest. Alternate translation: "when Zechariah was priest" (See: [[rc://en/ta/man/jit/figs-metonymy]])