(The following is from Who is Jesus Christ? Unlocking the Mystery in the Gospel of Matthew, pp. 133-134.)

In Acts, Luke relates that the Church in its earliest days was united in purpose and action:

They devoted themselves to the apostles’ teaching and fellowship, to the breaking of bread and the prayers.
— Acts 2:42

This description shows the vital relationship between the “breaking of the bread” and achieving true fellowship. As the Shepherd of the Church, Jesus has remained with his sheep, keeping them united in one flock, primarily through the sacrament of the Eucharist — the “breaking of the bread,” which is the sacrament of unity. The Eucharist binds the Church into a mystical communion that is impossible through any human means. Simply put, without the Eucharist, there is no Church: “The Eucharist makes the Church” (CCC 1395). Examining the history of the Church, one cannot but marvel that it still even exists today; the attacks from both within and without have been constant and, at times, brutal. From heresies arising from the bosom of the Church to persecutions launched by the state, the gates of hell have not relented in their assaults (cf. Mt 16:18). How could a purely human institution survive through the centuries against such opposition? But the Church has the benefit of a divine Shepherd who not only watches over his flock but gives his body as the very food by which it can remain united and strong.

From the very origins of the Church, her Eucharistic unity is clearly visible. St. Paul writes to the church in Corinth:

The cup of blessing which we bless, is it not a participation in the blood of Christ? The bread which we break, is it not a participation in the body of Christ? Because there is one bread, we who are many are one body, for we all partake of the one bread.
—1 Cor 10:16-18

It is through participation in the Eucharist that Christ’s followers become more than just a likeminded group of people — they become one body. The Eucharist unites the Church to the saving act of Jesus on the cross, making her part of the world’s redemption.

The Eucharist binds its recipients not only to the Lord but also to each other. In a very real way, the bond a partaker of the Eucharist has with his fellow communicants is deeper than that of flesh and blood. Biological unity is of the flesh, but Eucharistic unity is of the Spirit of God. Christ said in his Eucharistic discourse, “It is the spirit that gives life, the flesh is of no avail” (Jn 6:63). Each member of the Church is a true brother and sister in the Lord, and the Church is the family of God. A family may have arguments or disagreements, but nothing can make two of its members cease to be part of the same family. Likewise, the Church cannot be divided as long as it is united in the Eucharist.