The Lord said to Moses and Aaron in the land of Egypt: This month shall mark for you the beginning of months; it shall be the first month of the year for you. Tell the whole congregation of Israel that on the tenth of this month they are to take a lamb for each family, a lamb for each household. If a household is too small for a whole lamb, it shall join its closest neighbor in obtaining one; the lamb shall be divided in proportion to the number of people who eat of it. Your lamb shall be without blemish, a year-old male; you may take it from the sheep or from the goats. You shall keep it until the fourteenth day of this month; then the whole assembled congregation of Israel shall slaughter it at twilight. They shall take some of the blood and put it on the two doorposts and the lintel of the houses in which they eat it. They shall eat the lamb that same night; they shall eat it roasted over the fire with unleavened bread and bitter herbs. Do not eat any of it raw or boiled in water, but roasted over the fire, with its head, legs, and inner organs. You shall let none of it remain until the morning; anything that remains until the morning you shall burn. This is how you shall eat it: your loins girded, your sandals on your feet, and your staff in your hand; and you shall eat it hurriedly. It is the passover of the Lord. For I will pass through the land of Egypt that night, and I will strike down every firstborn in the land of Egypt, both human beings and animals; on all the gods of Egypt I will execute judgments: I am the Lord. The blood shall be a sign for you on the houses where you live: when I see the blood, I will pass over you, and no plague shall destroy you when I strike the land of Egypt. Exodus 12:1-13 (NRSV)
On the first day of Unleavened Bread the disciples came to Jesus, saying, “Where do you want us to make the preparations for you to eat the Passover?” He said, “Go into the city to a certain man, and say to him, ‘The Teacher says, My time is near; I will keep the Passover at your house with my disciples.’” So the disciples did as Jesus had directed them, and they prepared the Passover meal. Matthew 26:17-19 (NRSV)
While they were eating, Jesus took a loaf of bread, and after blessing it he broke it, gave it to the disciples, and said, “Take, eat; this is my body.” Then he took a cup, and after giving thanks he gave it to them, saying, “Drink from it, all of you; for this is my blood of the covenant, which is poured out for many for the forgiveness of sins. Matthew 26:26-28 (NRSV)
The Last Supper takes place as Jesus and His disciples are celebrating the Passover. There are many parallels between the Passover and Jesus’ institution of the Sacrament of the Altar, so it was fitting that Jesus instituted this Sacrament as part of the fulfillment of the covenant between God and man.
A lamb without blemish is to be sacrificed. Not a defective lamb that would have been culled anyway, but a perfect lamb is to be offered. Jesus was the only acceptable sacrifice for God, because He was sinless and without blemish.
When Jesus speaks of His Blood being poured out as the new covenant, it is His Blood poured out for us that takes away our sin- we are no longer subject to the penalty for our sin. We are passed over, just as the Israelites were passed over by the Angel of Death when they put the lamb’s blood on the door frames of their homes.
For the Lord will pass through to strike down the Egyptians; when he sees the blood on the lintel and on the two doorposts, the Lord will pass over that door and will not allow the destroyer to enter your houses to strike you down. Exodus 12:23 (NRSV)
The beauty of the Sacrament (as it is the fulfillment of the Passover celebration) is that Jesus invites us to the table often. Not just once a year, but as the needs of the people dictate. In some churches Communion is celebrated monthly, or even at every service. He knows that we need His healing and sustenance on a regular basis, even as we pray, “Give us our daily bread.”
And we have, in the first place, the clear text in the very words of Christ: Do this in remembrance of Me. These are bidding and commanding words by which all who would be Christians are enjoined to partake of this Sacrament. Therefore, whoever would be a disciple of Christ, with whom He here speaks, must also consider and observe this, not from compulsion, as being forced by men, but in obedience to the Lord Jesus Christ, and to please Him. However, if you say: But the words are added, As oft as ye do it; there He compels no one, but leaves it to our free choice, answer: That is true, yet it is not written that we should never do so. Yea, just because He speaks the words, As oft as ye do it, it is nevertheless implied that we should do it often; and it is added for the reason that He wishes to have the Sacrament free, not limited to special times, like the Passover of the Jews, which they were obliged to eat only once a year, and that just upon the fourteenth day of the first full moon in the evening, and which they must not vary a day. As if He would say by these words: I institute a Passover or Supper for you which you shall enjoy not only once a year, just upon this evening, but often, when and where you will, according to every one’s opportunity and necessity, bound to no place or appointed time… from the explanation of the Sacrament of the Altar, Martin Luther’s Large Catechism