Receiving Communion is not just a sign of unity; it creates unity.
Before Communion, as all sing the Agnus Dei, the presiding priest breaks the host, the "Eucharistic Bread" that is Christ's Body. The Mass instructions (GIRM 83) say this gesture "signifies that the many believers are made one body by receiving Communion from the one Bread of Life which is Christ." Paul says (1Corinthians 10:17): "Because there is one bread, we who are many are one body, for we all partake of the one bread.
Sadly, there are divisions among us; almost as many as there are individual persons in the assembly. So Jesus, who in his Incarnation, "though he was in the form of God… emptied himself… being born in human likeness" (Philippians 2:6) now, though he is "one bread," divides himself to enter into the body of every person receiving Communion. This is to show he is making us, "who are many," one as the Three Persons of the Trinity are one, "in the unity of the Holy Spirit" (John 17:11, 22).
Saint Cyril of Alexandria wrote:
To merge us in unity with God and among ourselves, although we have each a distinct personality, the only Son devised a wonderful means... We are... molded into one sole body in Christ, feeding on one flesh alone. One Spirit singles us out for unity
ACTION: During Communion, watch Jesus giving himself to everyone there. Absorb what that means.
PRAYER: Lord, though we are many, make us "one Body, one Spirit in Christ."