I’ve written before of the promise of Matthew 18:20 (“For where two or three are gathered…”) in context. Because context matters, and it is abundantly clear that the “two or three” are not the folks who show up to your prayer meeting.
Amy K. Hall recently published a terrific piece making the same point, and I recommend you check it out. Not only because she agrees with me and makes the same point I do. But because she sees something I never noticed about why Jesus promises to be with these two or three folks who represent him. The allusion to 2 Chronicles 19:5-7 is quite remarkable.