Moses took the blood of the sacrifice and poured half of it upon the altar, and with the other half he sprinkled the people as well as the Book of the Law, saying (as it says in Hebrews 9:20), “’Behold, this is the blood of the covenant,’ or testament. By this blood it is testified that God has established friendship with you. He has declared what He requires of you, you have declared what you will do. He will be your God, you will be His people.”
Valerius Herberger, The Great Works of God: The Mysteries of Christ in the Book of Exodus, VI.27
Locus Communis 