Question: I am an ex-Protestant and I hope to be received into full communion with  the Catholic Church. I am not so much eager to become a Catholic, as I am eager to be united with the True Church that Christ founded (and I do believe there can be only one, not many), and to follow the apostles teaching.

Answer:

Tragically you mistake the Roman Catholic Church for the one true church of Jesus Christ. You want to become catholic - and yet by joining the Church of Rome, you will become "Catholic" in name only and not in truth. In Christian theology the word "catholic" describes the entire church of Jesus Christ. The  word "catholic" simple means "universal". All God's people from every nation and in every era, all who are redeemed by the blood of Jesus, together form the catholic church.

The Lord Jesus has one universal - or catholic - church. He is the head, and all the redeemed are members of His body.

"...the church is subject to Christ...Christ also loved the church and gave Himself for her, that He might sanctify and cleanse her with the washing of water by the word, that He might present her to Himself a glorious church, not having spot or wrinkle or any such  thing, but that she should be holy and without blemish...For we are  members of His body, of His flesh and of His bones." (See Ephesians 5:24-30).

Aren't Evangelical Christians subject to Christ since they follow the teaching of His Word? Doesn't Christ love them too? Didn't He give Himself on the  cross for them also? Yes surely, and therefore Evangelicals are members of His body, the catholic church! But when Rome boasts that it is the one and only true church of Christ, what shall we conclude? Shall we say that Christ loved and died for Roman Catholics only?

In the New Testament, every local congregation is called a church, and in this sense, there are many churches. The distinguishing feature of a true church of Christ is not the submission to the church  of Rome, but faithfulness to the teaching of Christ and love for the brethren (John 8:31; John 13:35). The various churches we read about in  the New Testament, though undoubtedly different in character and emphasis, recognized each other as members of the same one true church  of Jesus Christ. They were genuinely catholic and universal in their outlook.

But you, recognizing only the Roman church as the one true church of  Christ, would immediately exclude the millions of faithful Christian churches in the Orthodox, Waldensian, Protestant, Baptist and other  traditions. That is certainly against the spirit of catholicism we read in the Bible.

John Gerstner argues:
Strictly speaking "Roman Catholic" is a contradiction of terms. Catholic means universal; Roman denotes a particular place. It is the Protestant and not the Romanist who believes in the catholic church. Protestants believe the church is universal or catholic; Rome cannot discover it beyond her own communion (Gerstner J., The Gospel According to Rome).

As a Baptist you did not regard your denomination as the exclusive church of Jesus Christ, did you? You regarded other churches as valid manifestations of His Church, despite the differences in some doctrines and practices. You embraced all Christians as dear brothers and sisters in Christ despite the different denominational labels. What happened since then that compels you to look at the church from such a narrow and sectarian perspective? No denomination or local assembly is perfect in doctrine or practice. The reality is that the church, God's family, is found in all the local assemblies of Christians that believe in Him, obey His Word and love the brethren (imperfectly and yet truly).