We should be wholeheartedly committed to prayer. However, this passage is not teaching us about a “prayer of agreement”. It is intended as a further statement regarding the authority of the church and its leaders in discipline situations. The agreement part is in relation to the process employed in verses 15 through 17 that results in the decision to expel the unrepentant person from the fellowship.
Yet some say this text teaches that if two or more Christians agree in prayer about any specific issue, God will accomplish the prayer. If that is so, then why doesn’t God answer all our corporate prayers in accordance with our desires? Obviously, this passage clearly teaches more than what it simply says.
This was Christ telling the disciples that the Heavenly Father would ratify the decision of the church leaders. This wasn’t about giving church leaders or “prayer partners” unlimited authority. It was Jesus telling us, in principle, that when proper disciplinary procedures are followed in the church, the leaders have the right to deny fellowship to the defiant rebel who won’t repent of their major doctrinal, moral, or schismatic failure.
The binding and loosing has to do with the disciplinary decisions being made; God vests a certain authority to the church (cf.1 Corinthians 6:1-8). The gospel truth is that submitting to God means that we also have to submit to one another. This text is no proof that people don’t have to go to church, but rather, this passage is one that speaks directly and clearly to the reality of some kind of formal church organization.
What Jesus intended, some churches and individuals twist as they neglect the process of church discipline and shun church membership. Thus, certain portions of Jesus’ word (Matthew 18:19-20) are used to justify a lack of obedience to other portions of His word (Matthew 18:15-18). This may seem unimportant to you, but I don’t agree. Martin Luther’s instruction rings true here: it is better to be divided by truth than united by error.