Verse 18. For there is verily a disannulling. A setting aside. The law which existed before in regard to the priesthood becomes now abrogated, in consequence of the change which has been made in the priesthood. See Barnes "Heb 7:12".

Of the commandment. Relating to the office of priest, or to the ceremonial rites in general. This does not refer to the moral law, as if that was abrogated, for

(1) the reasoning of the apostle does not pertain to that, and

(2) that law cannot be abrogated. It grows out of the nature of things, and must be perpetual and universal.

Going before. Going before the Christian dispensation, and introducing it.

For the weakness and unprofitableness thereof. That is, it was not adapted to save man; it had not power to accomplish what was necessary to be done in human salvation. It answered the end for which it was designed -- that of introducing a more perfect plan, and then vanished as a matter of course. It did not expiate guilt; it did not give peace to the conscience; it did not produce perfection, (Heb 7:11,) and therefore it gave place to a better system.

{b} "weakness" Ac 13:39