William Burkitt on Hebrews 7:27

That is, "As Jesus Christ, our great High Priest, had no sin of his own to expiate, like other high priests, but his business was to offer for our sins; so the oblation and offering he made upon that account, was not bullocks or rams, but himself in sacrifice, and that once, and but once upon the cross, which once offered sacrifice was abundantly sufficient to take away sin; whereas other high priests offered for their own sins, and for the people's sins, and that often which was a token of their insufficiency and imperfection."

Learn hence, That no sacrifice could bring us to God, and save us to perfection, but that wherein the Son of God himself was both priest and offering; such and High Priest became us who offered himself once for all.

Learn, 2. That the perfection of Christ's sacrifice makes the repetition of it needless, and the often repeating of it would argue the imperfection both of priest and sacrifice: He needeth not daily to offer up sacrifice, for this he did once, when he offered up himself.