John Calvin Commentary Hebrews 7:27

"who needeth not daily, like those high priests, to offer up sacrifices, first for his own sins, and then for the [sins] of the people: for this he did once for all, when he offered up himself." — Hebrews 7:27 (ASV)

Who needs not, and so on. He pursues the contrast between Christ and the Levitical priests; and he points out especially two defects, so to speak, in the ancient priesthood, by which it appears that it was not perfect. And here, indeed, he only touches briefly on the subject; but he later explains every particular more fully, and particularly that which refers to the daily sacrifices, as the main question concerned these.

I will now also briefly touch on the several points. One of the defects of the ancient priesthood was that the high priest offered sacrifices for his own sins; how then could he have pacified God for others, when God was justly displeased with him? Then they were by no means equal to the work of expiating for sins. The other defect was that they offered various sacrifices daily; it therefore follows, that there was no real expiation, for sins remain when purgation is repeated. The case with Christ was wholly different; for he himself needed no sacrifice, as he was unstained by any spot of sin; and such was the sacrifice that it alone was sufficient until the end of the world, for he offered himself.