When you witness to a Roman Catholic, he will probably tell you he is a Christian and that his "church" is based on the Bible.  However, if you encourage him to read the Bible, he may decline.  One young Catholic lady told a soul winner: "If I read the Bible, I may interpret it wrong.  If I have a problem, I go to my priest and follow his council and I am okay."

In other words, the Catholic church is based on the Bible only as interpreted by the Priest.  There are many parallels between the Pharisees in Jesus` day and modern Roman Catholicism. 

Jesus told the Pharisees that they had made the word of God of no effect by their tradition. (Mark 7)  The Jewish leaders of Christ`s day had set themselves up as the final interpreters of the Scriptures and developed an elaborate set of traditions.  Jesus had some very harsh words for these leaders.

Roman Catholicism boasts that it also has a tradition called the "Magisterium."  It claims that this is the "Teaching Office" of the pope and the bishops.  Catholic laymen are told they cannot personally understand the Bible well enough to correctly interpret it.  They must go to Mother Church to find out what the Bible really says. 

Over the centuries, Papal decrees, ecumenical councils and conferences of bishops have built up a vast body of tradition that effectively redirects the people away from basic biblical teachings.  As with the Pharisees, they have "made the word of God of none effect."

Central to this body of tradition is the Eucharist.  By declaring that it becomes the actual body, blood and divinity of Jesus when blessed by the priest, they effectively force the people to come to them to "receive Jesus."  No longer can they develop a personal relationship with Him, but must rely on their "church" to perform a ritual for them.

In case the person really insists on praying to Jesus, they have a convenient stand-in, their Virgin Mary Goddess.  Jesus is cast as a formidable Judge best approached through His mother. If you want any kind of help from Him, you are more likely to get it by petitioning His mother, whom He is reluctant to refuse. And just to make it easy to reach her, you are given a convenient vain repetition: "Hail, Mary, Mother of God. Pray for us...." (See Matt. 6:7.)

These are the two traditional pillars keeping Roman Catholicism from collapsing.  The word of God tells us that Jesus desires a personal relationship with us.  All other religions remove His deity or obscure Him behind a cloud of ritual and unbiblical traditions.
Roman Catholicism is no exception.  You can see how they, also, have made the word of God of none effect through their traditions.  Soul winners, be not deceived by their pious claims of being the true Christian church.  The Pharisees claimed to be the true "believers," but Jesus called them hypocrites who made their disciples into "children of hell" through their traditions. (See Matt. 23:15.)