Catholics and the majority of Protestants agree that the end result of salvation is eternity in the presence of the Holy Trinity. However, our beliefs regarding the path to salvation could not be more different.
It would first help to understand why Protestants and Catholics - who both believe in Jesus Christ, His Redemptive Sacrifice and His written word, the Bible - have very different doctrines. The reason for the disagreement in doctrine comes down to authority. Catholics look to the Magesterium - the Pope and Bishops - for their teaching authority. The only authority outside of themselves that Protestants will listen to is the Bible.
But there is a big problem with the Protestant approach to the Bible because Protestants basically believe that each man is his own authority when it comes to Biblical interpretation. Protestants would never understand the Ethiopian described in Acts 8. The Ethiopian was reading scripture when the evangelist Philip said to him "Do you understand what you are reading?" The Ethiopian replied, "How can I unless someone explains it to me?"
