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 And, as the Levitical priesthood and the law are inseparably joined, since the former is repealed, the latter is so also (see on Heb 7:11).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).

JFB.