J. Ramsey Michaels on the use of "sacrifices" in Hebrews 9:23

far better sacrifices. The plural is surprising in that Christ’s offering of himself is more commonly pictured as a single sacrifice. The author has retained the plural for the sake of the parallel with “the blood of animals” (lit., “these”), and the plural lends itself to the assumption that although Christ’s sacrifice took place “once and for all” on the cross, his high priesthood, and consequently his priestly activity in heaven, is eternal and continual (for example, see 7:25). (Michaels, R. J. [2009]. Commentary on Hebrews. In Cornerstone Biblical Commentary: 1 Timothy, 2 Timothy, Titus, and Hebrews [Vol. 17, p. 408]. Carol Stream, IL: Tyndale House Publishers; emphasis added)