This is Paul writing to the believers at Corinth. That is proof that what Jesus had taught His inner circls of His disciples applies to all believers wishing to follow Him and serve Him as His disciples.
Did Jesus give the power to “bind and loose” to EVERYONE in Matt 16:19, 18:18?
Did Jesus give the power to forgive sins to EVERYONE in John 20:21-23?
Did Jesus give the power to cast out demons, cure the sick and raise the dead to EVERYONE in Matt 10:5-8?
To how many people did Jesus say, “feed my sheep” (John 21:15-19)? I believe it was to only ONE person … and guess who it was - surprise, surprise - it was Peter, the first Pope.
How come a replacement had to found for Judas in Acts 1? If an ordinary believer fell away or died, did the early Church officially appoint a replacement-believer?