Truly Jesus Himself
The Real Presence, Jesus Himself, lives in our Tabernacles. He is God's mystery, God's Gift, God's love. During the Holy Mass at the time of the Consecration, when the priest pronounces Jesus' divine words: "This is My Body.....This is the Chalice of My Blood" (Matt. 26:26-27), the bread and wine become the Body and Blood of Jesus. The substance of the bread and of the wine are no longer there, because they have been transformed - "transubstantiated" - into the divine Body and Blood of Jesus. The bread and wine keep only their appearances, to express the reality of food and drink, according to Jesus' words, "My Flesh is real food and My Blood is real drink" (John 6:56).
Behind the veil, the disguise, of the Host, and within the Chalice, there is the Divine Person of Jesus with His Body, Blood, Soul, and Divinity.
This is what is given to whoever receives Holy Communion, and is what continually remains in the consecrated Hosts placed in the tabernacle.
St. Ambrose wrote: "How is the change of bread into the Body of Christ brought about? It is by means of the Consecration. With what words is the Consecration accomplished? It is with the words of Jesus. When the moment arrives for accomplishing this sacred wonder, the priest ceases to speak as himself; he speaks in the person of Jesus."
The words of Consecration are the most wonderful and awesome words that God has given to the Church. They have the power, through the priest, to transform a bit of bread and wine into our crucified God, Jesus! They achieve this wonderful, mysterious feat by a supreme power which surpasses the power of Angels and belongs only to God and to His priests. We should not wonder that there have been holy priests who suffered a great deal when they pronounced those divine words.
St. Joseph of Copertino, and in our own time, Padre Pio of Pietrelcina, appeared visibly weighed down with distress, and they managed only with difficulty and with pauses to complete the formulas of Consecration. The Father Guardian ventured to ask St. Joseph of Copertino, "How is it you recite the whole Mass so well, and stammer at each syllable of the Consecration?" The Saint answered, "The sacred words of the Consecration are like burning coals on my lips. When I pronounce them, I have to do it like one who has to swallow boiling hot food."
It is through these divine words of Consecration that Jesus is on our altars, in our tabernacles, and in the Hosts. But how is it that all this comes about? "How is it possible," an educated Mohammedan asked a missionary bishop, "that bread and wine should become the Flesh and Blood of Christ?" The Bishop answered, "You were small when you were born. You grew big because your body changed the food you took into flesh and blood. If a man's body is able to transform bread and wine into flesh and blood, then God can do it far more easily."
The Mohammedan then asked: "How is it possible for Jesus to be wholly and entirely present in a little Host?" The bishop answered, "Look at the landscape before you and consider how much smaller your eye is in comparison to it. Now within your little eye there is an image of this vast countryside. Can God not do in reality, in His Person, what is done in us by way of a likeness or image?" Then the Mohammedan asked, "How is it possible for the same Body to be present at the same time in all your churches and in all the consecrated Hosts?"
The bishop said, "Nothing is impossible with God and this answer ought to be enough. But nature also answers this question. Let us take a mirror, throw it down on the floor and let it break into pieces. Every piece can carry the same image that the whole mirror formerly reproduced. Likewise, the self-same Jesus reproduces Himself, not as a mere likeness, but as a reality, in every consecrated Host. He is truly present in each One of Them."
"My heart feels as if it were being drawn by a superior force each morning just before uniting with Him in the Blessed Sacrament. I have such a thirst and hunger before receiving Him that it's a wonder I don't die of anxiety. I was hardly able to reach the Divine Prisoner in order to celebrate Mass. When Mass ended I remained with Jesus to render Him thanks. My thirst and hunger do not diminish after I have received Him in the Blessed Sacrament, but rather, increase steadily. Oh, how sweet was the conversation I held with Paradise this morning. The heart of Jesus and my own, if you will pardon the expression, fused. They were no longer two hearts beating but only one. My heart disappeared as if it were a drop in the ocean."
Source: Jesus, Our Eucharistic Love.