Please tell me where the Bible says specifically that the Catholic church is the "only" Church? I have never seen God's Word yield such a statement.
You are correct that the Bible does not contain the word "catholic." It is apparent in the New Testament, however, that Jesus is setting up a singular Church with leaders (Apostles) who should be heeded. If the leaders of the Church were not to be figures of authority, then why did the Corinthians, for example, heed the letters from Paul?
The argument then becomes "what happened to this Church in history?" We have to take our noses out of the Bible and look at human history. There are two possible choices for authoritative Churches which have existed since the beginning. Either the Catholics or Orthodox can point to the other and claim that they "broke away" from them first. All other Churches in the West at some point in history broke away from the original Catholic/Orthodox Church.
SD