“he that is not against us is for us” [Luke 9:50]
“he that is not against us is for us”. The disciples came across someone casting out demons in the name of Jesus and they invited him to join them. He declined for a reason we are not told, and the disciples told him to cease. Jesus upbraided them for this.
The disciples then and numerous times since have had to realise there are others doing the work of the Lord.
As Jesus intimated, folk are either for Him or against. Put another way, if you are not for Him, you are against Him. There is no middle road of disinterest. The challenge of the gospel calls men and women to call upon the Lord and be saved.
When you meet others who called and are saved, don’t forbid them because they don’t belong to your group!