18. there is—Greek, "there takes place," according to Ps 110:4.
disannuling—a repealing.
of the commandment—ordaining the Levitical priesthood. And, as the Levitical priesthood and the law are inseparably joined, since the former is repealed, the latter is so also (see on Heb 7:11).
going before—the legal ordinance introducing and giving place to the Christian, the antitypical and permanent end of the former.
weakness and unprofitableness—The opposite of "power" (Heb 7:16).