From the Gospel According to Matthew, 26th chapter (New Living Translation):
26 As they were eating, Jesus took a loaf of bread and asked God’s blessing on it. Then he broke it in pieces and gave it to the disciples, saying, “Take it and eat it, for this is my body.” 27 And he took a cup of wine and gave thanks to God for it. He gave it to them and said, “Each of you drink from it, 28 for this is my blood, which seals the covenant between God and his people. It is poured out to forgive the sins of many. 29 Mark my words � I will not drink wine again until the day I drink it new with you in my Father’s Kingdom.” 30 Then they sang a hymn and went out to the Mount of Olives.
I’m no biblical scholar, but my understanding is that Jesus is taking forms of an old covenant, an old agreement, between his people and God (of which, remarkably, he is a representative of both, because he’s fully both) to establish a new covenant. The old covenant’s way of resolving wrongs and trespasses (understood in terms of shed blood and broken bodies of a blemish-free lamb) and of remembrances of where God has brought the people from (the Passover, also celebrated this month, is the immediate context for the meal that Jesus and his disciples were eating for) is being both perfected and completed by the end of the week. In its place, Jesus stands as a testimony to the new testament, the new covenant.
The new covenant, well, we’ll get to that shortly.