What does Matthew 18:19 mean?
In these words, often misinterpreted and misapplied, Jesus is talking to the Twelve within the context of a sinful believer who is being removed from the community of Christians. These men will become the apostles of Jesus, given enormous power to represent Him on earth after He departs for heaven and the church is born. One power He will give to them is accurately presenting godly truth (John 14:25–26).Jesus does not give these men authority over heaven by saying that whatever they bind or loose on earth will be bound or loosed in heaven. Rather, when they describe a person as bound by sin or freed from sin, they are speaking truth. If they describe someone as included in the church or removed from it—according to these teachings of Jesus—that statement holds true. It is an enormous responsibility.
Likewise, Jesus' comments on prayer must be carefully understood. This promise follows the statement on binding and loosing, which itself is a continuation of remarks about church discipline. In this case, that seems to limit application to the disciples' prayer of removing a believer from the community for a refusal to repent. Again, this would be a very solemn and heavy responsibility.
It is drastically against the context of this passage to assume this is a promise from God that any two or three Christians who come together to ask for anything from God will receive what they ask for.