Hebrews 7:16

Who was made
Not as man, much less as God; but as a priest, constituted and appointed one:

not after the law of a carnal commandment:
either the ceremonial law in general, which was a carnal one, if we consider the persons to whom it belonged, the Israelites according to the flesh; it was incumbent upon, and might be performed by such who were only carnal; and it was performed by and for men that were in the flesh, or mortal; and if we consider the matter of it, the subject on which various of its rites were exercised was the flesh or body, and which were performed by manual operation; and the sacrifices of it were the flesh of beasts; and these were for the sins of the flesh, and for the removing the ceremonial uncleanness of it; and the virtue of them reached only to the purifying of the flesh; and the whole of it is distinct from the moral law, which is spiritual, and reaches to the spirit or soul of man; whereas this only was concerned about temporal and external things: or else the law of the priesthood is particularly intended; or that commandment which respected the priesthood of Aaron; which law regarded the carnal descent of his sons; enjoined a carnal inauguration of them, and provided for their succession and continuance in a carnal way; after which, Christ the great high priest did not become one:

but after the power of an endless life;
this may be understood either of the Gospel, according to which Christ is a priest; and which is called "life", in opposition to the law which is the ministration of death; and because it is the means of quickening dead sinners, and of reviving drooping saints; and points out Christ the way of life, and has brought life and immortality to light: and may be said to be "endless", in distinction from the law, which is temporary; and because it is itself permanent and everlasting; contains in it the promise of eternal life, and is the means of bringing souls unto it: and there is a "power" goes along with it; which distinguishes it from the weak and beggarly elements of the ceremonial law, which is abolished, because of the weakness of it; for it is attended with the power of the Spirit of God, and is the power of God unto salvation: or else this intends the endless life which Christ has, in and of himself; and which qualifies him for a priest; and stands opposed to the mortality of the priests, and to that law which could not secure them from it: the priests died, and the law by which they were priests could not prevent their death; Christ is the living God, the Prince of life, he had power to lay down his life as man, and power to take it up again; and his life, as man, is an endless one, which qualifies him for that part of his priestly office, his intercession and advocacy: or it may design that power, which his Father has given him as Mediator, of an endless life, both for himself and for all his people; and regards his ever living as a priest, and the perpetuity of and the continual virtue and efficacy of it.