Acts 20:11 “When Paul had gone up and had broken bread and eaten…” St. Paul explained clearly what “breaking bread” meant. 1 Cor 10:16 “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?” St. Paul continued, 1 Cor 11:27 “Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the Body and Blood of the Lord.” St. Paul in these words confirmed Catholic teaching that the “bread … of the Lord” is truly Christ’s Body, Blood, Soul and Divinity, and that the “cup of the Lord” is the same substance: “Whoever … eats the bread or drinks the cup … will be guilty of profaning the Body and Blood of the Lord.”
St. Paul added, 1 Cor 11:29 “For any one who eats and drinks without discerning the Body eats and drinks judgment upon himself.” If we receive the Holy Eucharist without acknowledging, at least in our hearts, that it is His true Body, Blood, Soul and Divinity, we send ourselves to hell.
Context is always key:
1 Corinthians 11:
17 Now in giving these instructions I do not praise you, since you come together not for the better but for the worse. 18 For first of all, when you come together as a church, I hear that there are divisions among you, and in part I believe it. 19 For there must also be factions among you, that those who are approved may be recognized among you. 20 Therefore when you come together in one place, it is not to eat the Lord’s Supper. 21 For in eating, each one takes his own supper ahead of others; and one is hungry and another is drunk. 22 What! Do you not have houses to eat and drink in? Or do you despise the church of God and shame those who have nothing? What shall I say to you? Shall I praise you in this? I do not praise you.
23 For I received from the Lord that which I also delivered to you: that the Lord Jesus on the same night in which He was betrayed took bread; 24 and when He had given thanks, He broke it and said, “Take, eat;[b] this is My body which is broken[c] for you; do this in remembrance of Me.” 25 In the same manner He also took the cup after supper, saying, “This cup is the new covenant in My blood. This do, as often as you drink it, in remembrance of Me.”
26 For as often as you eat this bread and drink this cup, you proclaim the Lord’s death till He comes.
27 Therefore whoever eats this bread or drinks this cup of the Lord in an unworthy manner will be guilty of the body and blood[d] of the Lord. 28 But let a man examine himself, and so let him eat of the bread and drink of the cup. 29 For he who eats and drinks in an unworthy manner[e] eats and drinks judgment to himself, not discerning the Lord’s[f] body. 30 For this reason many are weak and sick among you, and many sleep. 31 For if we would judge ourselves, we would not be judged. 32 But when we are judged, we are chastened by the Lord, that we may not be condemned with the world.
33 Therefore, my brethren, when you come together to eat, wait for one another. 34 But if anyone is hungry, let him eat at home, lest you come together for judgment. And the rest I will set in order when I come.