John Calvin Commentary Hebrews 12:24

"and to Jesus the mediator of a new covenant, and to the blood of sprinkling that speaketh better than [that of] Abel." — Hebrews 12:24 (ASV)

And to Jesus the Mediator, He adds this lastly, because it is He alone through whom the Father is reconciled to us, and who renders His face serene and lovely to us, so that we may come to Him without fear. At the same time, he shows how Christ becomes our Mediator, even through His own blood, which, in the Hebrew manner of speaking, he calls the blood of sprinkling, meaning sprinkled blood. For as it was once for all shed to make an atonement for us, so our souls must now be cleansed by it through faith. At the same time, the Apostle alludes to the ancient rite of the Law, which has been mentioned previously.

That speaketh better things, There is no reason why better may not be rendered adverbially in the following manner, — “Christ’s blood cries more efficaciously, and is better heard by God than the blood of Abel.” It is, however, preferable to take the words literally: the blood of Christ is said to speak better things, because it avails to obtain pardon for our sins. The blood of Abel did not properly cry out; for it was his murder that called for vengeance before God. But the blood of Christ cries out, and the atonement made by it is heard daily.