In OT times, God exercised authority over his people through the agency of prophets, priests and kings, whose respective work it was to proclaim his messages (Je. 1:7ff.), teach his laws (Dt. 31:11; Mal. 2:7) and rule in accordance with those laws (Dt. 17:18ff.). So doing, they were to be respected as God’s representatives, having authority from him. Also, written Scripture was acknowledged as God-given and authoritative, both as instruction (tôrâ) to teach Israelites their King’s mind (cf. Ps. 119) and as the statute-book by which he ruled and judged them (cf. 2 Ki. 22–23).
Packer, J. I. (1996). Authority. In D. R. W. Wood, I. H. Marshall, A. R. Millard, & D. J. Wiseman (Eds.), New Bible dictionary (3rd ed., p. 106). Leicester, England; Downers Grove, IL: InterVarsity Press.