Hebrews 7:11

11.If therefore perfection, or, moreover if perfection, (118) etc. From the same testimony the Apostle concludes, that the old covenant was abrogated by the coming of Christ. He has hitherto spoken of the office and person of the priest; but as God had instituted a priesthood for the purpose of ratifying the Law, the former being abolished, the latter necessarily ceases. That this may be better understood, we must bear in mind the general truth, — That no covenant between God and man is in force and ratified, except it rests on a priesthood. Hence the Apostle says, that the Law was introduced among the ancient people under the Levitical priesthood; by which he intimates, that it not only prevailed during the time of the Law, but that it was instituted, as we have said for the sake of confirming the Law.

He now reasons thus, If the ministry of the Church was perfect under the order of Aaron, why was it necessary to return to another order? For in perfection nothing can be changed. It then follows, that the ministry of the Law was not perfect, for that new order was to be introduced of which David speaks. (119)

For under it the people received the Law, etc. This parenthesis is inserted in order that we may know that the Law was annexed to the priesthood. The Apostle had in view to prove that in the Law of Moses there was no ultimate end at which we ought to stop. This he proves by the abrogation of the priesthoods and in this way: Had the authority of the ancient priesthood been such as to be sufficient fully to establish the Law, God would have never introduced in its place another and a different priesthood. Now, as some might doubt whether the abolition of the Law followed the abolition of the priesthood, he says that the Law was not only brought in under it, but that it was also by it established. (120)