We often talk about people “joining the church” when they accept Christ as their savior. Maybe there is nothing wrong with using this term, but it is not how the Bible refers to how new members become a part of the church.
In Acts 2 we read about how the church began on the day of Pentecost. Peter preached the gospel message and urged those who believed in the crucified and resurrected Jesus to repent and be baptized for the forgiveness of their sins (v.38). We read in verses 40-41, “With many other words he warned them; and he pleaded with them, ‘Save yourselves from this corrupt generation.’ Those who accepted his message were baptized, and about three thousand were added to their number that day.”
So, it doesn’t say that they “joined the church”. It says that they “were added”. This leads us to ask the question, “Who did the adding?” The answer is provided in v.47—“…And the Lord added to their number daily those who were being saved.”
Is there really a difference in saying someone was added to the church instead of saying that they joined it? Perhaps. If I join the church, I could get the idea that I set the terms of my membership. If the Lord adds me to the church, it is clear that he sets the terms.