I will give you the keys of the kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.” (Matthew 16:19)
Truly, I say to you, whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven. (Matthew 18:18)
I have heard two different types of interpretations of these passages. The first understands this to give power to the church leadership (whether at the level of the local pastor or the denomination as a whole) to legislate on matters not addressed (or not sufficiently clear) in Scripture. This often gets applied to morally questionable practices. For example, some Christians think it is morally wrong to wear jewelry while others think it is morally acceptable. To settle the dispute, a pastor will either “bind” the issue by prohibiting the use of jewelry among his congregants, or will “loose” the issue by allowing it. Whatever the pastor binds or looses on earth is also bound or loosed in heaven, so to disobey or contradict the pastor is to disobey God Himself.