For ye are not come unto the mount that might be touched, and that burned with fire, nor unto blackness, and darkness, and tempest, And the sound of a trumpet, and the voice of words…But ye are come unto mount Sion…and to Jesus the mediator of the new covenant, and to the blood of sprinkling, that speaketh better things than that of Abel. – Hebrews 12:18,19,22,24

Observe that on Sinai there was “the sound of a trumpet, and the voice of words, which voice they that heard entreated that the word should not be spoken to them anymore.” You look, therefore, under the new dispensation, for a voice, and you do not come to any till you reach the last object in the list, and there see “the blood of sprinkling that speaks.” Here, then, is the voice of the gospel; it is not the sound of a trumpet, nor the voice of words spoken in terrible majesty, but the blood speaks, and assuredly there is no sound more piercing, more potent, more prevailing. God heard the voice of Abel’s blood and visited Cain with deserved punishment for killing his brother, and the precious blood of Jesus Christ, the Son of God, cries in the ears of God with a voice which is ever heard. How can it be imagined that the Lord God should be deaf to the cry of His Son’s sacrifice? Lo, these many ages the blood has cried – “Forgive them! Forgive them! Accept them! Deliver them from going down into the pit, for I have found a ransom!”

The blood of sprinkling has a voice of instruction to us even as it has a voice of intercession with God. It cries to us, “See the evil of sin! See how God loves righteousness! See how He loves men! See how impossible it is for you to escape from the punishment of sin except by this great sacrifice in which the love and the justice of God equally appear! See how Jehovah spared not His own Son but freely delivered Him up for us all.” What a voice there is in the atonement! – a voice which pleads for holiness and love, for justice and grace, for truth and mercy. “See that you refuse not Him who speaks.” ~ C.H. Spurgeon

https://www.blueletterbible.org/comm/spurgeon_charles/sermons/1888.cfm