"As the consecration of the Mass draws near our Lord is equivalently saying to us: "You, Mary; you, John; you, Peter; and you, Andrew-you, all of you-give Me your body; give Me your blood. Give Me your whole self! I can suffer no more. I have passed through My cross, I have filled up the sufferings of My physical body, but I have not filled up the sufferings wanting to My Mystical Body, in which you are. The Mass is the moment when each one of you may literally fulfill My injunction: 'Take up your cross and follow Me.'"
On the cross our Blessed Lord was looking forward to you, hoping that one day you would be giving yourself to Him at the moment of consecration. Today, in the Mass, that hope our Blessed Lord entertained for you is fulfilled. When you assist at the Mass He expects you now actually to give Him yourself.
Then as the moment of consecration arrives, the priest in obedience to the words of our Lord, "Do this for a commemoration of me," takes bread in his hands and says "This is my body"; and then over the chalice of wine says, "This is the chalice of my blood of the new and eternal testament." He does not consecrate the bread and wine together, but separately.
The separate consecration of the bread and wine is a symbolic representation of the separation of body and blood, and since the Crucifixion entailed that very mystery, Calvary is thus renewed on our altar. But Christ, as has been said, is not alone on our altar; we are with Him. Hence the words of consecration have a double sense; the primary signification of the words is: "This is the Body of Christ; this is the Blood of Christ;" but the secondary signification is "This is my body; this is my blood."
Such is the purpose of life! To redeem ourselves in union with Christ; to apply His merits to our souls by being like Him in all things, even to His death on the Cross. He passed through His consecration on the Cross that we might now pass through ours in the Mass. There is nothing more tragic in all the world than wasted pain. Think of how much suffering there is in hospitals, among the poor, and the bereaved. Think also of how much of that suffering goes to waste! How many of those lonesome, suffering, abandoned, crucified souls are saying with our Lord at the moment of consecration, "This is my body. Take it"? And yet that is what we all should be saying at that second: I give myself to God. Here is my body – take it. Here is my blood – take it. Here is my soul, my will, my energy, my strength, my property, my wealth – all that I have: it is yours – take it! Consecrate it! Offer it! Offer it with thyself to the Heavenly Father in other that He, looking down on this great sacrifice, may see only, His beloved Son, in whom He is well pleased. Transmute the poor bread of my life into thy divine life, swirl the wine of my wasted life into thy divine spirit; unite my broken heart with thy heart; change my cross into a crucifix.
Let no my abandonment and my sorrow and my bereavement go to waste. Gather up the fragments, and as the drop of water is absorbed by the wine at the offertory of the Mass, let my life be absorbed in thine; let my little cross be entwined with the great cross so that I may purchase the joys of everlasting happiness in union with thee.
Consecrate these trial of my life which would go unrewarded unless united with thee; transubstantiate me so that like bread which is now thy body, and wine which is now thy blood, I too my be wholly thine. I care not if the species remain, or that, like the bread and the wine I seem to all earthly eyes the same as before. My station in life, my routine duties, my work, my family — all these are but the species of my life which remain unchanged; but the substance of my life: my soul, my mind, my will, my heart – transubstantiate them, transform them wholly into thy service, so that through me all may know how sweet is the life of Christ."
-- Calvary and the Mass by Archbishop Fulton Sheen