Is It Sinful for Catholics to leave the Catholic Church?

Apparently, my 2-day stay in my hometown, made me realized the situation of my parish. Some of the core leaders are more active in the Charismatic churches and even though they are still attending mass, but no longer active in the Church ministries.

Some of them left the Catholic Church already and now evangelizing the remaining Catholic to join them in the Protestant Charismatic churches. So far, the people that I asked about it said that it is okay as long as they could deepen their faith in the other churches, after all, all religions are good.

I guess the question is whether it would be sinful for a Catholic to leave the faith and join a non-Catholic Church.

In my opinion, it is. But the first objection that I often get is but Protestant churches are still worshipping The Trinity and Jesus is also the saviour, so what’s the difference?

The Catechism of the Catholic Church (CCC) states that “the Father willed to call the whole humanity together into His Son’s Church” (836,845).

836 “All men are called to this catholic unity of the People of God… and to it, in different ways, belong or are ordered: the Catholic faithful, others who believe in Christ, and finally all mankind, called by God’s grace to salvation” (LG 13)

845 To reunite all his children, scattered and led ashtray by sin, the Father willed to call the whole of humanity together into His Son’s Church. The Church is the place where humanity must rediscover its unity and salvation. The Church is “the world reconciled.” She is that bark which “in the full sail of the Lord’s cross, by the breath of the Holy Spirit, navigates safely in this world.” According to another image dear to the Church Fathers, she is prefigured by Noah’s ark, which alone saves from the flood.

The reason why God wants this unity because the (Catholic) Church possesses the fullness of truth and the ordinary means of grace necessary for growth in holiness. However this does not mean that everyone who leaves the Catholic Church is necessarily guilty of sin. It depends on whether the person knows – or should know – that God wills the person to belong to the Catholic Church (CCC 846-848).

As we all know, there are many ignorant Catholics who do not realize what they are doing is wrong. Hence, they may not be held accountable. On the other hand, someone who knows in his heart that God wills him to belong to Christ’s Church and rejects it, may very well to be held accountable. However, only God could judge such people as He is the only one who can truly know the heart of any one person. We must always pray for these people in the hope that they will come to see the Truth and return to the loving embrace of God’s holy family, the Church.