As with other important concepts within Christianity, it is important that we define terms related to theology. As I did previously with faith, I’m going to do the same thing with the term “church” this time. I will also be taking a look at the term “catholic” in regards to different organizational churches claiming to be “The Church.”
Church, in the greek is ekklesia. It is a noun (a femine form) that means, in Greek, “out-called ones” or an assembly gathered together usually for a purpose, or as a group connected by something. So, The Church is all of God’s outcalled ones, and members of The Church all proclaim Jesus is Lord. 1 Corinthians 1:2 Unto the church of God which is at Corinth, to them that are sanctified in Christ Jesus, called to be saints, with all that in every place call upon the name of Jesus Christ our Lord, both theirs and ours:
When you turn to God in faith, when you are born again, you are a part of His Church; of His out-called ones, regardless of denominational title. Now, of course there must be a correct and faithful understanding of Who Christ is, for you don’t want to commit idolatry in the sense that you need to make sure you are turning to God, and not something of your own making.
There are several denominations claiming to be “The” Church; that’s not how this works. Take the Roman church for example. They’ve attempted to co-opt the term “catholic” and there is great misunderstanding about this word, esp. amongst certain evangelical circles. The term “catholic” means universal.
When the early church writers talked of the catholic, or universal church they meant all believers everywhere, not just those in Rome. That’s the point. So, even today many denominations’ creeds rightly affirm that they believe in “the holy catholic Church.” This is why, to avoid confusion, I usually refer to “the Roman catholic church” as the Roman church; they began merely as the organizational church in Rome.
The true catholic Church is made up of all believers from every nation, every denomination, from every time. Think of the gospel like a town crier; it is proclaimed and everyone who responds, who comes out to gather at the sound of it are the out-called ones, the ekklesia, who have all responded to the cry and assemble together in Christ. We all become members of the Church upon our faith in Christ.
Also, there is definitely a difference between an earthly organizational church, and The Church proper. You can belong to a Baptist organizational church, a Methodist, Episcopalian, Pentecostal, Roman, etc… etc… organizational church an be a member of The Church, you may not belong to any organizational church, and still fully be a member of The Church.
Mark 9:38 And John answered him, saying, Master, we saw one casting out devils in thy name, and he followeth not us: and we forbad him, because he followeth not us. 39 But Jesus said, Forbid him not: for there is no man which shall do a miracle in my name, that can lightly speak evil of me. 40 For he that is not against us is on our part.

