To truly understand what Jesus did at the climax of his life—and what the Catholic Church does at every Mass—we must understand the importance of blood sacrifice to Judaism in Jesus’ time. Everything that Moses did at Mt. Sinai, and all that was done for a thousand years in the temple, was summed up by Christ’s ultimate blood sacrifice on the Cross, offered for the reconciliation of God and humanity. And this ultimate lifeblood of God, sprinkled by Christ the high priest once for all, is what the Mass re-presents and makes sacramentally present to us.