Read Romans 5:1-5
When we citizens of the twenty-first century think of blood, we think of a liquid made up of plasma, red and white corpuscles, platelets, hemoglobin and such stuff. We think of the heart pumping this liquid through the lungs to be oxygenated and through the kidneys to be purified. We think of leukemias, cancers of the blood that can kill. We think of blood transfusions that can save lives. In other words, we think like the amateur scientists and doctors that we all tend to be.
It’s hard to imagine that in Jesus’ time none of this was known. People didn’t even realize that blood circulates through the body. All they knew was that if you lost too much blood, you died. Blood is life.
And life is sacred. If you wanted to offer a sacrifice to God, you slaughtered an animal and poured out its blood on an altar. You offered the animal’s life to God.
A great reversal was brought about by Jesus. He poured out his blood for us. He made this clear on the night before he died: “Take and drink. This is the cup of my blood, the blood of the new covenant, which will be poured out for you.”
One final twist: for the Jewish tradition, the heart is not the seat of emotions, but of thought and will. To say that God’s love has been poured into our hearts does not entail sentimental considerations, but rather a new way of understanding and a new motivation for our choices. This is what the Spirit of Jesus brings to his disciples. This is the great work of the Father, the Son and the Spirit.