More sins means a false repentance from sin.
And, yet, that isn't taught anywhere in the NT. In fact, it is made very clear throughout that believers still struggle with sin.
1Co 1:11 For it has been reported to me by Chloe's people that there is quarreling among you, my brothers.
1Co 3:1 But I, brothers, could not address you as spiritual people, but
as people of the flesh, as infants in Christ.
1Co 3:2 I fed you with milk, not solid food, for you were not ready for it. And even now you are not yet ready,
1Co 3:3 for
you are still of the flesh. For while there is
jealousy and strife among you, are you not of the flesh and behaving only in a human way?
1Co 3:4 For when one says, “I follow Paul,” and another, “I follow Apollos,”
are you not being merely human?
1Co 5:1 It is actually reported that there is sexual immorality among you, and of a kind that is not tolerated even among pagans, for a man has his father's wife.
1Co 5:2
And you are arrogant! Ought you not rather to mourn? Let him who has done this be removed from among you.
1Co 6:7 To have lawsuits at all with one another is already a defeat for you. Why not rather suffer wrong? Why not rather be defrauded?
1Co 6:8 But
you yourselves wrong and defraud—even your own brothers!
1Co 8:9 But take care that this right of yours does not somehow become a stumbling block to the weak.
1Co 8:10 For if anyone sees you who have knowledge eating in an idol's temple, will he not be encouraged, if his conscience is weak, to eat food offered to idols?
1Co 8:11 And so by your knowledge
this weak person is destroyed, the brother for whom Christ died.
1Co 8:12 Thus,
sinning against your brothers and wounding their conscience when it is weak,
you sin against Christ.
1Co 10:6
Now these things took place as examples for us, that we might not desire evil as they did.
1Co 10:7
Do not be idolaters as some of them were; as it is written, “The people sat down to eat and drink and rose up to play.”
1Co 10:8
We must not indulge in sexual immorality as some of them did, and twenty-three thousand fell in a single day.
1Co 10:9
We must not put Christ to the test, as some of them did and were destroyed by serpents,
1Co 10:10
nor grumble, as some of them did and were destroyed by the Destroyer.
1Co 10:11 Now these things happened to them as an example, but
they were written down for our instruction, on whom the end of the ages has come.
1Co 10:12
Therefore let anyone who thinks that he stands take heed lest he fall.
1Co 10:13 No temptation has overtaken you that is not common to man. God is faithful, and he will not let you be tempted beyond your ability, but with the temptation he will also provide the way of escape, that you may be able to endure it.
1Co 10:14 Therefore,
my beloved, flee from idolatry.
1Co 11:28 Let a person examine himself, then, and so eat of the bread and drink of the cup.
1Co 11:29 For anyone who eats and drinks without discerning the body
eats and drinks judgment on himself.
1Co 11:30 T
hat is why many of you are weak and ill, and some have died.
1Co 11:31 But if we judged ourselves truly, we would not be judged.
1Co 11:32 But
when we are judged by the Lord, we are disciplined so that we may not be condemned along with the world.
1Jn 1:8
If we say we have no sin, we deceive ourselves, and the truth is not in us.
1Jn 1:9 If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.
1Jn 1:10
If we say we have not sinned, we make him a liar, and his word is not in us.
1Jn 2:1
My little children, I am writing these things to you so that you may not sin. But
if anyone does sin, we have an advocate with the Father, Jesus Christ the righteous.
1Jn 5:16
If anyone sees his brother committing a sin not leading to death, he shall ask, and God will give him life—to those who commit sins that do not lead to death. There is sin that leads to death; I do not say that one should pray for that.
1Jn 5:17
All wrongdoing is sin, but there is sin that does not lead to death.
(All ESV.)
That is just a small sampling showing that true believers were struggling with sin. Remember, all the NT letters were written to new or relatively new believers, and it was necessary to show them how to live as Christians. This is no different than today. We still wage war against the flesh but our lives aren't to be characterized by willful, unrepentant sin.