Hebrews 7:8

And here - In the Levitical priesthood. But there - In the case of Melchisedec. He of whom it is testified that he liveth - Who is not spoken of as one that died for another to succeed him; but is represented only as living, no mention being made either of his birth or death.

And here men that die receive tithes, The priests and Levites were not only men, and mortal men, subject to death, but they did die, and so did not continue, by reason of death, Heb 7:24 but there he receiveth them, of whom it is witnessed that he liveth; which is to be understood of Melchizedek; who is not opposed to men, as if he was not a man, nor to mortal men, but to men that die; nor is he said to be immortal, but to live: and this may respect the silence of the Scripture concerning him, which gives no account of his death; and may be interpreted of the perpetuity of his priesthood, and of his living in his antitype Christ; and the testimony concerning him is in Psa 110:

Christ, on the other hand, is, in His own person, "ever living after the power of an endless life" (Heb 7:16, 25). Melchisedec's death not being recorded, is expressed by the positive term "liveth," for the sake of bringing into prominence the antitype, Christ, of whom alone it is strictly and perfectly true, "that He liveth."

And here men that die receive tithes - Another point showing the inferiority of the Levitical priesthood. They who thus received tithes, though by the right to do this they asserted a superiority over their brethren, were mortal. Like others, they would soon die; and in regard to the most essential things they were on a level with their brethren. They had no exemption from sickness, affliction, or bereavement, and death came to them with just as much certainty as he approached other men. The meaning of this is, that they are mortal like their brethren, and the design is to show the inferiority of their office by this fact. Its obvious and natural signification, in the apprehension of the great mass of readers, would not be, as the meaning has been supposed to be, that it refers “to the brief and mutable condition of the Levitical priesthood;” see Stuart in loco. Such an interpretation would not occur to anyone if it were not to avoid the difficulty existing in the correlative member of the verse where it is said of Melchizedek that “he liveth.” But is the difficulty avoided then? Is it not as difficult to understand what is meant by his having an immutable and perpetual priesthood, as it is to know what is meant by his not dying literally? Is the one any more true than the other? Whatever difficulties, therefore, there may be, we are bound to adhere to the obvious sense of the expression here; a sense which furnishes also a just and forcible ground of comparison. […]