The Corinthian Church was at that time a baby Christian congregation, not "full" of sin. It's common for modern churches to have significant populations of various belief groups. In one church half the people grow tired of the new style of worhsip music, rap, loudness, big drums and a light show of all colors, so go eat breakfast together until the preaching hour. Much of what was reported of them is actually expected behavior, not sin. Some members have grown to trust a well spoken highly educated doctor of divinity, not wanting to hear a common speaker even though that one is more spiritually minded. Why would it be sin if the folks preferred one preacher over another? When the churches I've belonged to had to replace a preacher, they all have several "try out" and be searched out. Nowadays it's common to do an NCIC check, encouraged by police. They had multiple preachers coming by, each more appealing to some. One might preach the milk of the word, another trying to bring them into full maturity. Then they are voted on and "called". That's the kind of stuff of what 1 Cor 1 is mostly about.
As for 1 Cor 2, what you call "immaturity" was simply that that city was a major trading center full of culture, temples, wealth, and polished orators who excited hearers with high-minded ideas. Paul was saying he never tried to compete with that, but stuck to preaching the "foolishness" of Christ crucified. No doubt many complained about Paul's appearance and message being to common, all one subject, Christ, a reason other preachers might be preferred as greater orators. Paul continued to explain his ministry, that since they knew nothing about Jews nor Jesus it was vital to stick to milk of the word as though for babies, who could not handle the meat until raised up. I have witnessed churches that cycled though members by attrition, the first group dying or otherwise unable to attend, replaced by folks who never had Sunday School classes, or some switching from another denomination, and many other causes of significant ignorance of Christian ways. one of that is considered sin, and if spiritual immaturity is a sin, probably the majority of Christians are in sin would you say?
Seeing that part of that post was a mischaracterization of those people who are sometimes described by modern speakers as a building full of very wicked people sacrificing babies on the altar and doing every possible sin as a part of worship, it is necessary to deal with the presumption that taints the rest of this post. Some of them were formerly of that crowd doing some of the highly immoral things before being born again.
Here is His judgment concerning people who continue to do certain sins, without a qualification that those once sanctified are excused because all past, present, and future sins are washed away. How would that work if that person is found doing:
Revelation 21:6-8 (KJV)
6 And he said unto me, It is done. I am Alpha and Omega, the beginning and the end. I will give unto him that is athirst of the fountain of the water of life freely.
7 He that overcometh shall inherit all things; and I will be his God, and he shall be my son.
8 But the fearful,
and unbelieving,
and the abominable,
and murderers,
and whoremongers,
and sorcerers,
and idolaters,
and all liars,
shall have their part in the lake which burneth with fire and brimstone: which is the second death.
Grace is not there to excuse people to add sin to sins washed away. It is well explained this way
Galatians 2:15-21 (KJV)
15 We who are Jews by nature, and not sinners of the Gentiles,
16 Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified.
17 But if, while we seek to be justified by Christ, we ourselves also are found sinners, is therefore Christ the minister of sin? God forbid.
18 For if I build again the things which I destroyed, I make myself a transgressor.
19 For I through the law am dead to the law, that I might live unto God.
20 I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me.
21 I do not frustrate the grace of God: for if righteousness come by the law, then Christ is dead in vain.
Perish the thought that God would stand up in defense of a person claiming to be His child, who has a "problem" of selling dangerous drugs to school children walking to school. Just a "mistake"? He would continue to hold that person, who introduces children to a horrible lifestyle of drug abuse and brain damage, slavery, and horrible deaths is still justified in Christ because there was a time when the drug dealer believed the gospel and repented of that crime?
No. Not possible. Grace doesn't allow a sinner to keep returning to his vomit like a dog and still please God or expect blessings from Him.
Proverbs 26:11-12 (KJV)
11 As a dog returneth to his vomit, so a fool returneth to his folly.
12 Seest thou a man wise in his own conceit? there is more hope of a fool than of him.
That is repeated by Peter concerning such as false teachers and other backsliders, using that proverb to have such people "like" dogs and pigs.
.
2 Peter 2:19-22 (KJV)
19 While they promise them liberty, they themselves are the servants of corruption: for of whom a man is overcome, of the same is he brought in bondage.
20 For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning.
21 For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them.
22 But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.
Will you then say Paul was teaching LAW in the following?
Hebrews 6:1-8 (KJV)
1 Therefore leaving the principles of the doctrine of Christ, let us go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God,
2 Of the doctrine of baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgment.
3 And this will we do, if God permit.
4 For it is impossible for those
who were once enlightened,
and have tasted of the heavenly gift,
and were made partakers of the Holy Ghost,
5 And have tasted the good word of God, and the powers of the world to come,
6 If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.
7 For the earth which drinketh in the rain that cometh oft upon it, and bringeth forth herbs meet for them by whom it is dressed, receiveth blessing from God:
8 But that which beareth thorns and briers is rejected, and is nigh unto cursing; whose end is to be burned.
