I am fully convinced that no Catholic on planet Earth can debate me without leaving the Bible and having to use extra-Biblical sources, this does not come from a smugness or arrogance, it comes from years of experience.
The first issue in disproving Catholicism is their "communion of the saints" now they'll say they don't actually pray to the dead saints, but they merely ask them to intercede on their own behalf. Then I simply ask them...
"Where do we find anybody in the bible, praying to someone who has passed on to intercede for them? I want to see evidence of Peter petitioning Noah, Paul petitioning David, John petitioning Abraham, Stephen petitioning Elijah etc... We see no evidence at all of this happening in scriptures. Surely if this was an important thing in the early church, if there was any truth at all to it, it would have happened SOMEWHERE in the Bible from Genesis to Revelation."
An educated Catholic may resort to Revelation and talking about the 24 elders with the prayers of the saints, but that is alot of twisting on the side of Catholicism. They must first establish that these people are the dead saints of Catholicism, and they must prove secondly that the prayers of the saints are intercessory prayerss, and not their own prayers. Neither is indicated by scriptures.
An educated Catholic might also try to establish that "nobody is really dead in Christ, so our prayers to the saints are as real and as personal as if you spoke to your own neighbor or family". They will then follow up with this verse. Mat 22:32 I am the God of Abraham, and the God of Isaac, and the God of Jacob? God is not the God of the dead, but of the living. Some Catholics take this as meaning people are not literally dead in Christ.
I will first of all say that's an erroneous interpretation of that scripture. He was talking to the Sadducees, so claiming that saints are still alive in the same paragraph that Jesus is referring to the resurrection of the dead, is not wise. To prove it with scriptures, we need look no further than Rom 14:9 For to this end Christ both died, and rose, and revived, that he might be Lord both of the dead and living. This verse proves that yes, there are dead people that Jesus is the Lord of. This takes care of the sometimes Catholic interpretation of Mat 22:32 Getting back to Catholicism....
The next point I bring up and ask is about the irrefutible authority of the church, that some Catholics believe the church cannot ever be wrong. I bring up Galileo, who was confined under house arrest for the last years of his life by none other than the Catholic church, for saying that the Earth went around the Sun.
So tell me, can the church be wrong? If they can be wrong about that, what else could they be wrong about? Nothing indicates that the Catholic church has always been the same, I seriously doubt the church of Galileo's time was the same as the first century church, and it sure as heck isn't the same as today's Catholicism.
Regarding Mary, I need to point out that she did not remain a virgin. Mark 6:3 mentioning Jesus's brothers and sisters I'll admit can be taken more than one way, but how about Mat 1:24-25 Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife: And knew her not till she had brought forth her firstborn son: and he called his name JESUS.
Joseph and Mary clearly consumated their marriage at some point after Christ was born.
Take into account also John 2:12 which says "After this he went down to Capernaum, he, and his mother, and his brethren, and his disciples: and they continued there not many days." If by "brethren" it meant "disciples" then it would have been redundant, because it says disciples right after that. If when it said "brethren" it meant cousins or kinsmen, the word in the Greek would have been suggenes, and not adelphos, which is derived from the Greek word for womb and means brother. We know Joseph was alive at least until Jesus was 12, since he is present during the temple incident. Do Catholics really believe that she and Joseph never had sex in those 12 years? Virgin mother she may be, but was she not a good wife? Even then, if you know female anatomy, the act of childbirth would remove her virginity would it not?
On Peter and Papal celibacy, if Peter really was the first Pope, he was certainly married. Mat 8:14, not only mentions Peter's wife, but also Peter's mother-in-law, and why would any man have a mother-in-law unless they were married? Furthermore 1st Tim 3:2 says that a bishop should be the husband of one wife, yet Catholic bishops are forbidden to marry. Proof that this cannot be interpretated as 'married to the church' reverts back to the fact that Peter had a literal flesh and blood wife.
The last thing I bring up is the office of the Pope. Where is this office in the Bible? It mentions it nowhere.
No Catholic can answer these questions without using sources outside of the Bible, Catholics rely solely on tradition. Getting your beliefs from 'sola scriptura' (latin for scriptures only) is very important. You don't have to believe every single line in the entire Bible for salvation, but if you could use other sources, then why not the book of Mormon too? How about the writings of Ellen G. White and the Seventh Day Adventists while we're at it? Let's also throw in some new age writings, and if tradition is what's important, why not adopt some Judaism? The point is, it's a dangerous path to get doctrines from outside of the Bible, and the Catholic faith relies on such doctrines.
As a parting shot, here is something to point out to Catholics from one of their own sacred publications....
�For the Son of God became man so that we might become God.�
St. Athanasius De Inc., 54, 3: PG 25, 192B.
Official Catholic Doctrine from Catechism of the Catholic Church Ignatius Press p. 116 (p. 129 in 2nd ed by Doubleday)
See also: St. Thomas Aquinas, Opusc. 57:1-4 and St. Irenaeus, Adv. Haeres. 3, 19, 1: PG 71, 939
St. Athanasius De Inc., 54, 3: PG 25, 192B.
St. Augustine's own words, "...so that man can become God." Which sounds like the same lie repeated since the garden of Eden, trying to get man on God's throne, with power and authority and exaltation. Just like the Mormon belief that someday everyone will be a god, and have our own planet.
And in The Dialogue of Saint Catherine of Siena, God the Father told her: "taking your humanity, and, freeing you from the servitude of the devil, I made you free. And if you examine, you will see that man has become God, and God has become man, through the union of the divine with the human nature."
Discussion between myself and Paul Swonger