All true believers who put their faith in Christ alone through faith alone are part of the ekklesia of Christ, those called out by God to be His. I belong to that ekklesia. I claim no "membership" or "belonging" to any man made organization. I belong to Christ alone and He is my High Priest. I can meet and worship with any like minded whether it's in a group of three or hundreds. I have found that it matters not what name the group calls itself as long as they remain true to scripture.
A comment my grandfather made when I was about 14 years old has remained with me all these years. He said with a finger point up "He is who you put your faith in" then with his finger pointing to the the "church" said "it's not them". Again with his finger pointing up said "he is who died for you" and again pointing to the "church" said "it's not them". He worshipped faithfully his entire life in one "church" but I knew that day that he truly belonged to Christ not to that "church".
Thank you, I agree with you and your wise grandfather.
“Christ Alone”