My beloved ones, avoid idolatry.
I am speaking as to sensible people;
judge for yourselves what I am saying.
The cup of blessing that we bless,
is it not a participation in the Blood of Christ?
The bread that we break,
is it not a participation in the Body of Christ?
Because the loaf of bread is one,
we, though many, are one Body,
for we all partake of the one loaf.
Saint Paul, a citizen of the Roman Empire but Jewish to his core, never forgot the spiritual perils of idolatry and slavery. "For freedom Christ set you free!" he thundered in his Letter to the Galatians.
He and his people were intimately familiar with both dangers. A huge percentage of the Roman world were slaves. Conquering armies routinely forced natives from their own lands and replaced them with subjected people of other lands; they were all slaves and subjects of their new emperors. Demoralized by the failure of their native gods they readily accepted the worship of new gods even as they learned to eat strange foods. Inevitably their children and grandchilren forgot their homelands and native customs just as many Americans have forgotten their European origins.
Jews, however, from the time of their Babylonian exile, had never surrendered the worship of God. He went with them into exile, according to the Prophet Ezekiel who saw the Lord whipping about the heavens on his fiery chariot. If they were forced to submit publicly to alien rulers they worshipped the Lord and kept the Law in the privacy of their homes.
When Jerusalem and the Temple were destroyed in 70 AD, the Jewish/Christian apostle never batted an eye; God's worship would continue with the cup of blessing and the breaking of bread. So long as we have this ceremony we are free.
The threat for Catholics in the United States is still very real. Many have wandered off to join oxymoronic "non-denominational christian churches." Many more speak of "God" without reference to the Trinity of Father, Son and Spirit. They claim to pray without attending any church.
But their children abandon that hypocritical language and find other gods to worship: pleasure, power, money, entertainment, drugs and so forth. Or they seek "spirituality" in Eastern mysticism or parody religions.
To keep our communion with one another and the Lord, to avoid idolatry and maintain our freedom, we bless the cup and break the bread each Sunday, and we sing the song of the Lord in a foreign land.