Dear Arwin,
My advice to you is to pick up you bible and read the following sections: John 6:24-71, Luke 22:19-22, Mark 14:22-24, Matt 25:26-38, Matt 10:32-33, John 14:21, Acts 20:7, 1 Cor 10:16 and 11:17-27.
Most of these verses confirm the doctrine of transubstantiation, the Eucharistic proclamation of faith based on love for the Lord, and the normative practice of receiving the Eucharist every Sunday.
However, I’d like you to hone in on 1 Cor 11:17-27 which should answer your concerns about Catholic exclusivity with regards to the Eucharist. Notice St. Paul’s warnings about disunity among the members of the church as he elaborates on the Lord’s Supper:
“What I now have to say is not said in praise, because your meetings are not profitable but harmful. First of all, I hear that when you gather for a meeting there are divisions among you, and I am inclined to believe it. There may even have to be factions among you for the tried and true to stand out clearly. When you assemble it is not to eat the Lord’s Supper, for everyone is in haste to eat his own supper. One person goes hungry while another gets drunk. Do you not have homes where you can eat and drink? Would you show contempt for the church of God, and embarrass those who have nothing? What can I say to you? Shall I praise you? Certainly not in this matter.” (emphasis mine)
The point made by St. Paul is that where congregants meet to partake of the Eucharist there should be no disunity among them. Otherwise, the meetings themselves would be sinful in as much as when the poor are being denied sacramental grace which was apparently the practice in the Corinthian church. And to allow protestants to partake of the Eucharist would be even more grave according to St. Paul:
“I received from the Lord what I handed on to you… Every time, then, you eat this bread and drink this cup, you proclaim the death of the Lord, until he comes! This means that whoever eats the bread or drinks the cup of the Lord unworthily sins against the body and blood of the Lord.” (emphasis mine)
As you can see from St. Paul’s warning, if a priest were to allow a professing protestant to partake of the Eucharist, he would be just as culpable and liable for the sin of eathing unworthly being committed by the protestant believer! Therefore it is for your own protection that Catholics along with their priests must insist that you refrain from participation lest you place your soul in grave danger of sinning against the body and blood of our Lord. This is done out of love, not snobbery, and is in conformity to scripture which always confirms Catholic teaching.
The Catholic Church also holds her children to the exact standard by insisting that we can not partake of protestant communion for the same reason lest we sin against the body and blood of our Lord. It would be remiss of us to say the least to take communion at a Lutheran church, and very disrespectful of deeply-held protestant beliefs to act as if our doctrinal differences and disunity do not matter to God.
I hope these biblical teachings help you in your faith journey. And I hope that Catholics reading my response will learn to strengthen their otherwise very good arguments with the bible. God bless you, Arwin.
Captain Michael Trust
U.S. Army
Baghdad, Iraq