11 If the priesthood of Levi and Aaron, which provided the framework for the giving of the law, could really make people perfect, there wouldn't have been need for a new priesthood like that of Melchizedek. 12 But since it didn't get the job done, there was a change of priesthood, which brought with it a radical new kind of law. 13 There is no way of understanding this in terms of the old Levitical priesthood, 14 which is why there is nothing in Jesus' family tree connecting him with that priestly line.
Matthew Henry's Commentary on Hebrews 7:11-14
Commentary on Hebrews 7:11-25
(Read Hebrews 7:11-25)
The priesthood and law by which perfection could not come, are done away; a Priest is risen, and a dispensation now set up, by which true believers may be made perfect. That there is such a change is plain. The law which made the Levitical priesthood, showed that the priests were frail, dying creatures, not able to save their own lives, much less could they save the souls of those who came to them. But the High Priest of our profession holds his office by the power of endless life in himself; not only to keep himself alive, but to give spiritual and eternal life to all who rely upon his sacrifice and intercession. The better covenant, of which Jesus was the Surety, is not here contrasted with the covenant of works, by which every transgressor is shut up under the curse. It is distinguished from the Sinai covenant with Israel, and the legal dispensation under which the church so long remained. The better covenant brought the church and every believer into clearer light, more perfect liberty, and more abundant privileges. In the order of Aaron there was a multitude of priests, of high priests one after another; but in the priesthood of Christ there is only one and the same. This is the believer's safety and happiness, that this everlasting High Priest is able to save to the uttermost, in all times, in all cases. Surely then it becomes us to desire a spirituality and holiness, as much beyond those of the Old Testament believers, as our advantages exceed theirs.