In the Old Testament, God demanded sacrifices to make atonement for sins(Lev 17:11). However, in the New Testament it says, “…For it is not possible that the blood of bulls and goats could take away sins” (Hebrews 10:1-4). In order to figure out this conundrum, we first make a distinction between those ceremonies/sacred works which are sacraments and those which are sacrifices. Next, we make a distinction between the two kinds of sacrifices: propitiatory and eucharistic. Our high Priest, according to both His human and divine natures, made the only propitiatory sacrifice to merit the forgiveness of sins. All other sacrifices are eucharistic sacrifices, which do not merit forgiveness, but instead give honor and thanks to God for the forgiveness of sins which a person has already received.
The Apology to the Augsburg Confession, XXIV, 27 makes it clear that, “The Jews also did not understand their ceremonies aright, and imagined that they were righteous before God when they had wrought works ex opere operato. Against this the prophets contend with the greatest earnestness.” The Old Testament Prophets continued to condemn the opinion of the people who thought that God was pleased with works-righteous sacrifices, simply on account of their having done the work apart from faith.