why the feast must focus on Mary? The feast is about Christ’s institution of the Eucharist. While I believe that Mary was in the Upper Room at the Last Supper, the Last Supper was not about her - it was about the Eucharist.
I would not suggest focusing on Mary, but rather showing the relevance of Mary to the Eucharist, in this way (I’m not a homilist, but I am a catechist):
The Eucharist - the gift of this most sacred food from heaven - is the result of two crucial events:
The eternal Son needed to 1) become a man, 2) to die for us - to give His life for our redemption, and to enable our resurrection to eternal life in Him and in His resurrection from the dead.
- Mary was present for the Incarnation. Her self-gift in obedience to God - her fiat - her “yes” - enabled the Incarnation. Hers was the first human experience of God become man, for our salvation. The Body of Christ, which we receive [in its resurrection glory] in Eucharist, came first into and through Mary, His mother.
- Mary was present at His death on the Cross, with the Apostle John. She was given, from the Cross, Motherhood of the Church to be, in the person of the Apostle John as her first son after Jesus.
Mary was the first recipient of mankind’s promise of resurrection in His resurrection from the dead, in her Assumption into heaven, body and soul.
In that context, listen to Jesus’s teachings concerning
Holy Eucharist, and
our resurrection:
Joh 6:38 For I have come down from heaven, not to do my own will, but the will of him who sent me;
Joh 6:39 and this is the will of him who sent me, that I should lose nothing of all that he has given me, but raise it up at the last day.
Joh 6:40 For this is the will of my Father, that
every one who sees the Son and believes in him should have eternal life; and I will raise him up at the last day."
…
Joh 6:50
This is the bread which comes down from heaven, that a man may eat of it and not die.
Joh 6:51 I am the living bread which came down from heaven;
if any one eats of this bread, he will live for ever; and the bread which I shall give for the life of the world is my flesh."
Joh 6:52 The Jews then disputed among themselves, saying, “How can this man give us his flesh to eat?”
Joh 6:53 So Jesus said to them, "Truly, truly, I say to you,
unless you eat the flesh of the Son of man and drink his blood, you have no life in you;
Joh 6:54
he who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day.
Joh 6:55 For my flesh is food indeed, and my blood is drink indeed.
Joh 6:56 He who eats my flesh and drinks my blood abides in me, and I in him.
I hope it can be seen, that the Eucharist - the resurrection Body and Blood of our Lord - is the food for our resurrection, the food for our resurrection bodies. This is clear from verses 53-54 above. And His Body and Blood came to us by and through Mary - not just her body, but her grace-filled Faith. And her role in our lives continues, because Jesus made her our Mother in Christ.
We ought to know, and treasure, her part in our salvation in her Son.