The authority to “bind” and to “loose” which was given to Peter (Matt 18:18) would have been readily understood by the Jewish audience that Matthew was writing to.
The authority to “bind” means the authority to forbid, and the authority to “loose” means the authority to permit. Jesus assured Peter (and, by extension, his successors, the Popes, and the Magesterium) that they had authority both on earth and in heaven to forbid or permit certain acts.
This authority gives force to the precepts of the Church. These precepts are not doctrinal, and may change over time. Yet, Catholics are bound by them. For example, Catholics were once permitted to eat meat on any Friday, and later forbidden from eating meat on any Friday, and later permitted on any Friday except during Lent. These are precepts, but willful disobedience could constitute mortal sin.
A precept is not doctrine, yet a Catholic may be culpable of mortal sin for willfully violating a precept. Why is this? Where does the Church have the authority to declare a particular act mortally sinful today, and not sinful (in any way) tomorrow? (or the other way around?)
I refer you to Matthew 18:18 for the answer. It is not only the *doctrine *of the Church that Catholics are expected to respect, but also the *precepts *(rules). The *rules *of the Church are enforced even in Heaven, as Jesus assured us when he gave His Church the authority to “permit” or “forbid” - anything (literally, anything - read the passage).
That’s a pretty broad scope of authority. That’s the Catholic Church.
