Christ is going to save only one ekklesia, so it behooves all of us to be in the right one. Ekklesia is defined in Thayer’s Greek Lexicon as follows: “a gathering of citizens called out from their homes into some public place; an assembly.”
This term is used in the Bible with this general sense, for example, in Acts 19 when the people assembled during the riot in Ephesus. Christ used this term in Matthew 16:18 referring to a group of followers who would believe him to be the Son of the living God. Caesarea Philippi—the location where Peter made his confession concerning Christ—has significance because the region was a religious center where people practiced pagan worship. There must have been many ekklesias during that period. Christ highlighted that he would build his own ekklesia. Thus, we know that there is an ekklesia of Christ.
Related to Christ’s use of the word, Paul employs ekklesia to refer to a company of Christians located in different regions (See 1 Corinthians 4:17, Romans 16:1, and Colossians 4:16). This is not to say that Christ has different ekklesias. All those who have believed in Christ and have gone through the conversion experience described in various parts of the Book of Acts have been added to Christ’s ekklesia (e.g., Acts 2:38-47). Paul simply used the term to refer to a congregation or gathering of those believers. Modern English Bible translations use terms such as congregation, assembly, and church, the latter probably being the most common. The church is the body of Christ, and to be saved, you must be in that body because Christ is the Savior of the church:
“And He put all things under His feet, and gave Him to be head over all things to the church, which is His body, the fullness of Him who fills all in all” (Eph. 1:22-23).
“For the husband is head of the wife, as also Christ is head of the church; and He is the Savior of the body” (Eph. 5:23).
Christ is coming for his church, not the Baptist church, the Pentecostal church, the Methodist church, the Catholic church, the Orthodox church, the Episcopalian church, the community church, etc. He is going to save the church that he purchased with his blood, the church that is made up of those who have been called out of darkness into his marvelous light (Acts 20:28; 1 Pet. 2:9). That ekklesia is the church of Christ—the body of Christ.