A Reading for Maundy Thursday --Matthew 26:17-30
17 Now on the first day of Unleavened Bread the disciples came to Jesus, saying, “Where will you have us prepare for you to eat the Passover?” 18 He said, “Go into the city to a certain man and say to him, ‘The Teacher says, My time is at hand. I will keep the Passover at your house with my disciples.’” 19 And the disciples did as Jesus had directed them, and they prepared the Passover.
20 When it was evening, he reclined at table with the twelve. 21 And as they were eating, he said, “Truly, I say to you, one of you will betray me.” 22 And they were very sorrowful and began to say to him one after another, “Is it I, Lord?” 23 He answered, “He who has dipped his hand in the dish with me will betray me. 24 The Son of Man goes as it is written of him, but woe to that man by whom the Son of Man is betrayed! It would have been better for that man if he had not been born.” 25 Judas, who would betray him, answered, “Is it I, Rabbi?” He said to him, “You have said so.”
26 Now as they were eating, Jesus took bread, and after blessing it broke it and gave it to the disciples, and said, “Take, eat; this is my body.” 27 And he took a cup, and when he had given thanks he gave it to them, saying, “Drink of it, all of you, 28 for this is my blood of the covenant, which is poured out for many for the forgiveness of sins. 29 I tell you I will not drink again of this fruit of the vine until that day when I drink it new with you in my Father's kingdom.”
From the Heidelberg Catechism--Lord's Day 28
75. How is it signified and sealed to you in the Holy Supper that you partake of the one sacrifice of Christ on the cross and all His benefits?
Thus: that Christ has commanded me and all believers to eat of this broken bread and to drink of this cup in remembrance of Him, and has joined therewith these promises: first, that His body was offered and broken on the cross for me and His blood shed for me, as certainly as I see with my eyes the bread of the Lord broken for me and the cup communicated to me; and further, that with His crucified body and shed blood He Himself feeds and nourishes my soul to everlasting life, as certainly as I receive from the hand of the minister and taste with my mouth the bread and cup of the Lord, which are given me as certain tokens of the body and blood of Christ.
 Mt 26:26-28; Mk 14:22-24; Lk 22:19-20; 1 Cor 10:16-17, 11:23-25, 12:13
76. What does it mean to eat the crucified body and drink the shed blood of Christ?
It means not only to embrace with a believing heart all the sufferings and death of Christ, and thereby to obtain the forgiveness of sins and life eternal; but moreover, also, to be so united more and more to His sacred body by the Holy Spirit, who dwells both in Christ and in us, that, although He is in heaven and we on earth, we are nevertheless flesh of His flesh and bone of His bone, and live and are governed forever by one Spirit, as members of the same body are governed by one soul.
 Jn 6:35, 40, 47-48, 50-54;  Jn 6:55-56; 1 Cor 12:13;  Acts 1:9-11, 3:21; 1 Cor 11:26; Col 3:1;  1 Cor 6:15, 17, 19; Eph 3:16-19, 5:29-30, 32; 1 Jn 4:13;  Jn 6:56-58, 63, 14:23, 15:1-6; Eph 4:15-16; 1 Jn 3:24
77. Where has Christ promised that He will thus feed and nourish believers with His body and blood as certainly as they eat of this broken bread and drink of this cup?
In the institution of the Supper, which says: “The Lord Jesus the same night in which He was betrayed took bread: and when He had given thanks, He broke it, and said, Take, eat: this is my body, which is broken for you: this do in remembrance of me. After the same manner also He took the cup, when He had eaten, saying, This cup is the new covenant in my blood: this do, as often as you drink it, in remembrance of me. For as often as you eat this bread, and drink this cup, you proclaim the Lord’s death till He come.” And this promise is also repeated by the Apostle Paul, where he says: “The cup of blessing which we bless, is it not the communion of the blood of Christ? The bread which we break, is it not the communion of the body of Christ? Because there is one bread, so we being many are one body, for we are all partakers of that one bread.”
 1 Cor 11:23-25;  1 Cor 10:16-17