There are several passages in the Bible that teach fellowship between churches. There are enough to know that, first, fellowship did occur between true churches. “Fellowship” is a technical word. It is used in the world in a certain sense, but it is technical in that there is a distinct, biblical understanding of fellowship. A good place to start on “fellowship” is 2 Corinthians 6:14, which says, “Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness with unrighteousness?” Obviously not everyone is to fellowship according to this verse, but I draw your attention to its meaning, enlightened by the words “yoked together.” Fellowship involves being yoked together, which means doing work together, and in the context work of a spiritual nature. Fellowship is not just being in the same room and talking. It is associating together in a common endeavor. Scriptural doctrine and practice is the biggest factor to determine who a church should work with. Light can’t fellowship with darkness. However, churches that believe and practice the same should fellowship, and this is seen among references in 3 John, it’s one chapter. The church there was to receive “fellowhelpers to the truth,” who are on a journey “after a godly sort.” “The truth” and godliness are part of the criteria. In Romans 12:13, Paul said churches should be “given to hospitality” and Peter said (1 Pet 4:9), “Use hospitality.” Churches of the same truth and godliness should welcome and receive one another, enter into common work, which is to be fellowhelpers to each other.