Repentance

Your reasoning is flawed. Paul wrote to the saints, the sancitified in Christ Jesus. He was writing to Christians. The fact that there were some that were not saved among the sanctifed in Corinth, to whom he wrote to, is totally irrelevant.

John had the same problem didn't he.

1 John 2:19 They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.

It wasn't really a problem. It is just a fact. It is a fact that somehow, someway false teachers will sneak into the churches and lead some astray. It happens. However in John's case, the church was strong enough that the false teachers could be identified because they would not continue in a church that was well grounded in the Word. They would not remain faithful "because they were not of us."

What did Paul say of the church at Ephesus?
Acts 20:29-30 For I know this, that after my departing shall grievous wolves enter in among you, not sparing the flock. Also of your own selves shall men arise, speaking perverse things, to draw away disciples after them.
--This was both a warning and a prophecy. He knew this was going to happen. He knew that false teachers (greivous wolves) would enter in... speaking perverse things to draw away disciples after them.

This was not uncomon. It was not just in the church at Corinth.

What did happen to the Ephesian church?
Revelation 2:4-5 Nevertheless I have somewhat against thee, because thou hast left thy first love. Remember therefore from whence thou art fallen, and repent, and do the first works; or else I will come unto thee quickly, and will remove thy candlestick out of his place, except thou repent.
--They did lose their first love, and eventually their candlestick was removed.

Sorrow doesn't save. Christ does.

 

You have. You have stated that without remorse or sorrow for sin that there is no repentance which is necessary for salvation. But sorrow doesnt save. It isn't necessary for salvation. Christ saves; not sorrow.

You need to read my quotes more carefully. Really, it hasn't made your work any easier. Consider, especially 1John 2:19

1 John 2:19 They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.

Bob, read carefully. These false teachers were never part of the church in the first place. John makes this very clear. They were not of us. They were never members. They were never part of the church. Just because there is a body that occupies a place on the pew doesn't make that body a member of the church. John makes that clear.

Now, let's go back to 1Cor.1, as you did, and see who Paul was really writing to:

1 Corinthians 1:2 Unto the church of God which is at Corinth, to them that are sanctified in Christ Jesus, called to be saints, with all that in every place call upon the name of Jesus Christ our Lord, both theirs and ours:

It is odd that you didn't quote verse two. He wrote to those that are sanctified; the saved. They were already justified; their sins paid for with the blood of Jesus Christ. They were "sanctified in Christ Jesus." That is one of the strongest statements of a positional standing in Christ Jesus that a Christian can have. Paul was writing to the believers in Christ--to the Christians at Corinth. The fact that there were some false teachers present among them is irrelevant. They were not part of the church. They were there among the church, not a part of it.
Let me give you an example. The preacher's son just went to Bible college. But guess what? Satan went too.

Now look at the Acts 20 passage more carefully:

Acts 20:29 For I know this, that after my departing shall grievous wolves enter in among you, not sparing the flock.
--Again, it is among you, not a part of you. They were no a part of the church of Ephesus. They were there, present, among the members--but not a part of the church. Wolves are not a part of the flock of sheep. They try to meander in and throughout the flock seeking whom they may get. But they certainly are not a part of the flock of sheep. The same is true of any false teacher. They are not part of the church. There is a big difference between the prepositions: "among" and "a part of."