This does not correspond to the book of Jeremiah (ch. 33). It is a Christian add-on. The OT does not say anything about anything dying before the New Covenant becomes "valid". That is something the Christians made up on the fly. The New Covenant was meant for the Jews and Jews only, the House of Judah and the House of Israel, with god inscribing his laws in their hearts; no one had to die and shed blood for that. The New Covenant did not "replace" the Old Covenant, as the book of Hebrews alleges (ch. 8), because God's covenant with the Jewish people is forever. The book of Hebrews was written for gullible, naive and superstitious Greeks who knew nothing of the Old Testament or Judaism.
So an agnostic is telling us the bible is wrong..how surprising