The great treasure of the Catholic Church is the Eucharist -- Jesus himself hidden under the appearances of bread and wine. We believe, as the Catechism states, that "In the most blessed sacrament of the Eucharist 'the body and blood, together with the soul and divinity, of our Lord Jesus Christ and, therefore, the whole Christ is truly, really, and substantially contained'" (CCC 1374).
Additionally, this Real Presence of Christ in the Eucharist does not end immediately when we receive him at Communion time. The Catechism goes on to explain how, "The Eucharistic presence of Christ begins at the moment of the consecration and endures as long as the Eucharistic species subsist" (CCC 1377).
What does that mean when we receive him into our mouths? How long does Jesus' Real Presence remain in our bodies?
There is a famous story from the life of St. Philip Neri that helps answer that question. One day while he was celebrating Mass, a man received Holy Communion and left the church early. The man appeared to have no regard for the Presence within him and so Philip Neri decided to use this opportunity as a teaching moment. He sent two altar boys with lighted candles to follow the man outside of the church. After a while walking through the streets of Rome, the man turned around to see the altar boys still following him. Confused, the man returned to the church and asked Philip Neri why he sent the altar boys. Saint Philip Neri responded by saying, "We have to pay proper respect to Our Lord, Whom you are carrying away with you. Since you neglect to adore Him, I sent two acolytes to take your place." The man was stunned by the response and resolved to be more aware of God's presence in the future.
It is generally assumed that the Eucharistic species of bread remains for about 15 minutes after reception. This is based on simple biology and reflects the Catechism's statement that the presence of Christ "endures as long as the Eucharistic species subsist."
This is why many saints have recommended offering 15 minutes of prayer after receiving the Eucharist as a thanksgiving to God. This allows the soul to savor the presence of God and have a true "heart-to-heart" with Jesus.
In our face paced world it is often difficult to remain long after Mass, but that doesn't mean we can't at least pray a brief prayer of thanksgiving. The main point is that we need to remember Jesus' presence in the Eucharist stays with us for several minutes and presents us with a special time when we can commune with our Lord and feel his love within us.
If one day you forget, don't be surprised if your parish priest sends altar servers to follow you to your car when you leave Mass early!
