The Service of Holy Communion
The Lutheran Hymnary  p. 72: 20-27

The Words of Institution are the inspired words of the Gospels (Matthew, Mark, and Luke) and of St. Paul (I Corinthians 11).  It is the Word of Christ that, together with the eating and drinking of the bread and wine that makes this supper the sacrament of Christ’s body and blood.  So we confess in the Small Catechism:

THE NATURE OF THE SACRAMENT OF THE ALTAR
           

What is the Sacrament of the Altar?

The Sacrament of the Altar is the true body and blood of our Lord Jesus Christ, under the bread and wine, instituted by Christ himself, for us Christians to eat and to drink.

Where is this written?

The holy evangelists Matthew,  Mark and Luke, together with St. Paul, write thus: "Our Lord Jesus Christ, the same night in which He was betrayed, took bread; and when He had given thanks, He broke it and gave it to His disciples, saying, 'Take, eat; this is My body, which is given for you. Do this in remembrance of Me.' In the same way also He took the cup after supper, gave thanks and gave it to them, saying, Drink from it, all of you; this cup is the New Testament in My blood, which is shed for you for the remission of sins. Do this, as often as you drink it, in remembrance of Me.’”

Following the Words of Institution is the Pax Domini, the Peace of the Lord, for by the gift of His body and blood, crucified and risen for the sins of the world, true peace is made between God and man, and full forgiveness of all our guilt is given personally to us.

Then comes the Agnus Dei, the Lamb of God, for Christ, the very Lamb of God who came to take upon Himself the sins of the world, is now with us, body and blood, together with the bread and wine of the Lord’s Supper, and is given to us in the Distribution.  In the distribution we receive with the body and blood together with the bread and wine.  With them we also receive the forgiveness of sins that Christ Himself promises.