Christ Jesus, who died, yes, who was raised from the dead, who is at the right hand of God, who indeed intercedes for us, is present in many ways to his Church: in his word, in his Church’s prayer, where two or three are gathered in my name, in the poor, the sick, and the imprisoned, in the sacraments of which he is the author, in the sacrifice of the Mass, and in the person of the minister. But he is present . . . most especially in the Eucharistic species. (CCC 1373)
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. (CCC 1374)
It is by the conversion of the bread and wine into Christ’s body and blood that Christ becomes present in this sacrament. The Church Fathers strongly affirmed the faith of the Church in the efficacy of the Word of Christ and of the action of the Holy Spirit to bring about this conversion. Thus St. John Chrysostom declares: It is not man that causes the things offered to become the Body and Blood of Christ, but he who was crucified for us, Christ himself. the priest, in the role of Christ, pronounces these words, but their power and grace are God’s. This is my body, he says. This word transforms the things offered. And St. Ambrose says about this conversion: Be convinced that this is not what nature has formed, but what the blessing has consecrated. The power of the blessing prevails over that of nature, because by the blessing nature itself is changed…. Could not Christ’s word, which can make from nothing what did not exist, change existing things into what they were not before? It is no less a feat to give things their original nature than to change their nature. (CCC 1375)
In the liturgy of the Mass we express our faith in the real presence of Christ under the species of bread and wine by, among other ways, genuflecting or bowing deeply as a sign of adoration of the Lord. The Catholic Church has always offered and still offers to the sacrament of the Eucharist the cult of adoration, not only during Mass, but also outside of it, reserving the consecrated hosts with the utmost care, exposing them to the solemn veneration of the faithful, and carrying them in procession. (CCC 1378)
It is highly fitting that Christ should have wanted to remain present to his Church in this unique way. Since Christ was about to take his departure from his own in his visible form, he wanted to give us his sacramental presence; since he was about to offer himself on the cross to save us, he wanted us to have the memorial of the love with which he loved us to the end, even to the giving of his life. In his Eucharistic presence he remains mysteriously in our midst as the one who loved us and gave himself up for us, and he remains under signs that express and communicate this love: The Church and the world have a great need for Eucharistic worship. Jesus awaits us in this sacrament of love. Let us not refuse the time to go to meet him in adoration, in contemplation full of faith, and open to making amends for the serious offenses and crimes of the world. Let our adoration never cease. (CCC 1380)