(15) “And if your brother sins against you, go and show him his fault between you and him alone. If he hears you, you have won your brother.
(16) But if he does not hear, take along with you one or two more, so that ‘by the mouth of two or three witnesses every word may be established.’
(17) But if he refuses to hear them, tell it to the assembly. But if he refuses even to hear the assembly, let him be to you as a heathen and a tax collector.
(18) Assuredly I say to you, whatever you bind on earth shall have been bound in heaven, and whatever you loose on earth shall have been loosed in heaven.
(19) Again, assuredly I say to you that if two of you agree on earth about anything that they may ask, it will be done for them by My Father in heaven.
(20) For where two or three are gathered together in My name, I am there in their midst.”
It seems reasonable to take this passage as a cohesive statement. There’s much truth here, more than meets the eye.
Our Lord deals with discipline within a community of believers, and it’s proper process.
The unrepentant believer eventually, at the end of the process, gets banned from the assembly (vs. 17).
Our Lord then says that the decision, which the assembly comes to agreement on, is binding in heaven as well as the earth (vs. 18).
Then He says that even if 2 or 3 agree on such decisions, it’s with the same authority as the full assembly (vs. 19).
Then, He introduces another aspect : broadens it beyond disciplinary issues, He says that if the 2 or 3 agree concerning ANYTHING they ask it shall be done for them, and that He will be in their midst (vs. 19-20).
Here where we live, our whole definition of church really is based on this : that is, the main reason we assemble together is to agree in prayer concerning whatever things the Holy Spirit would have us pray for. Of course, there’s much more than prayer, but we do recognize God’s main purpose in bringing us together is what our Lord said here.
Then, in vs. 20, our Lord says that this essential understanding of agreement in prayer, and agreement in righteous judgment, is the meaning of meeting in Jesus’ name.
Vs. 20 most certainly legitimizes the 2s or 3s who come together in Jesus’ name, but it wouldn’t be an assembly by the NT definition, that is, with a plural eldership, deacons, and various gifts in operation. It may be best to call the 2s and 3s ‘expressions’ of the Body of Christ, bcos they are legitimate, as Jesus said He will be there in the midst. If 2 or 3 is all we have, and there’s nothing we can do about increasing that number, then we can move forward anyway, and maybe God will give the increase. We are not held back just bcos we are not a fully fledged NT assembly. If Jesus is in the midst, then we can move forward following Him.