This is an especially important question in deciding who exactly has the authority to bind and loose as conferred in Mt 18:18—all Christian believers or the apostles and their successors alone?
In the beginning, there were only about 86 apostles: the original twelve (including Judas), Matthias, Paul, and the 72 sent out by Jesus. No more. But Jesus had more than 86 followers, or disciples, as the Gospels tell. I consider myself a disciple of Christ, not an apostle. Indeed, all the apostles were explicitly CHOSEN either by Christ himself (Paul and the Twelve, see John 6:70 and Acts 1:2) or by the apostles themselves as a group (Matthias). (The latter is also evidence of the concept of apostolic sucession with Catholic bishops as the apostles’ successors.)
In Mark 6:30 and Matt 10:1-5, the twelve are specifically referred to as apostles. The latter Matthew citation shows the interchangeability of the terms “disciples” and “apostles,” at least for the 12. For they are called the “12 disciples” in the first verse and the “12 apostles” in next one:
“And when he had called unto him his twelve disciples, he gave them power against unclean spirits, to cast them out, and to heal all manner of sickness and all manner of disease. Now the names of the twelve apostles are these; The first, Simon, who is called Peter, and Andrew his brother; James the son of Zebedee, and John his brother; Philip, and Bartholomew….”
Disciples are called; apostles are sent. All apostles are disciples; not all disciples become apostles.
At various times in Matthew, it says the “disciples” got in a boat (e.g. Mt 14:22). Is it plausible that this referred to all Jesus’ followers? Again, in Mt 19:25-28, Jesus speaks to his “disciples” and refers to “12 thrones, judging the 12 tribes of Israel” that will be theirs. See also Mt 20:17 which says “12 disciples.” The Last supper passage Mt 26:18-20 also refers to 12 disciples. Mt 28:16 refers to the “eleven disciples” (Judas had already betrayed Jesus).
Thus, it is quite clear that throughout the book of Matthew that the term “disciples” almost surely refers ONLY to the Twelve. And this makes sense: Matthew is the the most Jewish of the gospels and the Jews did not let just anyone make binding Scriptural interpretations! The notion of an authoritative hierarchy and the importance of tradition that came from Judaism were not done away with in the formation of Christianity.
Consequently, since Jesus is not speaking to a crowd of followers/disciples but to the Twelve in Mt 18 when he confers the authority to “bind and loose,” it is the Church leadership, NOT all Christians, who receive this authority. And this interpretation is born out in descriptions of Church organization in Acts and Paul’s letters as well as in the history of early Church practices.