 And this is my blood. And he goes on to give an explanation about how if one is not worthy of receiving Jesus in Holy Communion, as we call it nowadays in the Eucharist, then one should not receive because he would be guilty of the body and the blood of the Lord. In other words, murder. Or if one does not recognize or discern the body, he should not receive. Otherwise, he will be, in essence, trampling underfoot God's grace.