If someone says I believe in Jesus why must they become Catholic?

[Pink_cowgirl]

If someone says, I believe in Jesus, why do they need to convert to the Catholic faith. Isn’t everyone saved and will go to heaven if they believe in Jesus?

 

[Fr.Charles_Grondin]

Jesus said to him, “I am the way and the truth and the life." - John 14:6

I came so that they might have life and have it more abundantly. - John 10:10

When someone says “I believe in Jesus” its not guaranteed that they mean the same thing that the listener does. After all, there are many variations of beliefs about Jesus and what he taught throughout history. Some have believed Jesus wasn’t divine, others that he wasn’t fully human. Some have believed Jesus has already returned, others believe Jesus commands them to do things that other Christians find immoral.

The Church ensures that what is taught and believed about Jesus is true.

Imagine if someone said they believe in Jesus and they take the saying about cutting off your own hand literally. While they may not be culpable for their self-mutilation, it would certainly affect their life in a hugely negative way. The Church helps us to discern the true teachings of Jesus and their meaning. St. Paul warned against following interpretations of the Gospel that were not from the Apostles:

I am amazed that you are so quickly forsaking the one who called you by [the] grace [of Christ] for a different gospel (not that there is another). But there are some who are disturbing you and wish to pervert the gospel of Christ. But even if we or an angel from heaven should preach [to you] a gospel other than the one that we preached to you, let that one be accursed! - Galatians 1:6-8

But I am afraid that, as the serpent deceived Eve by his cunning, your thoughts may be corrupted from a sincere [and pure] commitment to Christ. For if someone comes and preaches another Jesus than the one we preached, or if you receive a different spirit from the one you received or a different gospel from the one you accepted, you put up with it well enough… For such people are false apostles, deceitful workers, who masquerade as apostles of Christ. - 2 Corinthians 11:3-4, 13

Changing even the smallest parts of the truth of Jesus Christ has implications far beyond the small change. Like a tiny pebble thrown into the water, the ripples of falsehood spread. The Church established by Jesus and entrusted to the Apostles and their successors is the only guarantee of truth:

If he refuses to listen even to the church, then treat him as you would a Gentile or a tax collector. - Matthew 18:17

And so I say to you, you are Peter, and upon this rock I will build my church, and the gates of the netherworld shall not prevail against it. l I will give you the keys to the kingdom of heaven. - Matthew 16:18