A - Thank you very much for your question! What an important question you ask. Let us examine the distinction of how Christ is present to us first. Vatican II states (Sacrosanctum Concilium, 7):
To accomplish so great a work, Christ is always present in His Church, especially in her liturgical celebrations. He is present in the sacrifice of the Mass, not only in the person of His minister, "the same now offering, through the ministry of priests, who formerly offered himself on the cross" (20), but especially under the eucharistic species. By His power He is present in the sacraments, so that when a man baptizes it is really Christ Himself who baptizes (21). He is present in His word, since it is He Himself who speaks when the holy scriptures are read in the Church. He is present, lastly, when the Church prays and sings, for He promised: "Where two or three are gathered together in my name, there am I in the midst of them" (Matt. 18:20) .So, the Church teaches that Christ is truly present to us in several different ways. He is present in the following ways:
- in Scripture
- in the congregation
- in the priest
- in the Sacraments
- in the Eucharist.
So, from this the Church teaches that the Sacrament of the Eucharist is the "Source and Summit" (Lumen Gentium, 11) of the Christian life. Therefore, there is no greater way to pray, to live and to worship than to be receive the Eucharist. It is Christ.
While our bodies are the temple of the Holy Spirit, we are united even more closely to Christ by celebrating the Eucharist. This is because we are sinners and our temples will be ever in need of renovation until we get to heaven.
Thus, John 6: 53-58 says:
I tell you the truth, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you. Whoever eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day. For my flesh is real food and my blood is real drink. Whoever eats my flesh and drinks my blood remains in me, and I in him. Just as the living Father sent me and I live because of the Father, so the one who feeds on me will live because of me. This is the bread that came down from heaven. Your forefathers ate manna and died, but he who feeds on this bread will live forever.Thus, by partaking of the Blessed Sacrament we are intimately united with Christ. The Catechism of the Catholic Church teaches in 1374 that:
The mode of Christ's presence under the Eucharistic species is unique. It raises the Eucharist above all the sacraments as "the perfection of the spiritual life and the end to which all the sacraments tend." 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." "This presence is called 'real' - by which is not intended to exclude the other types of presence as if they could not be 'real' too, but because it is presence in the fullest sense: that is to say, it is a substantial presence by which Christ, God and man, makes himself wholly and entirely present."For more on this topic, I highly recommend that you read CCC, 1322-1419.