[kosta50]

Who is the letter addressed to

Obviously to people who had no idea what they were doing. The Letters of Paul were sent to churches that needed "correction" of their course. It is clear that the Corinthians were following (believeing?) everyone but Jesus.

[irishtenor]

***It is clear that the Corinthians were following (believeing?) everyone but Jesus.***

No, it is not clear. Paul addresses them as "Sanctified in Christ Jesus and called to be holy..." They were believers, but like man everywhere, even in the church, error creeps in and tries to take over. That is why the scriptures are so important. Check everything by the scriptures of God.