It is written: "
Psalm 19:13,
NIV:
Keep your servant also from willful sins; may they not rule over me. Then I will be blameless, innocent of great transgression."
Peter had no intention/will to commit the sin. He sinned and fell out of weakness, not deliberately out of malice like Judas. Therefore, the Lord preserved his life, and gave him time to repent.
What Peter's example really shows is no one should guarantee himself that he will not fall away, because:
"“Do not boast about tomorrow, for you do not know what a day may bring forth.” (Prov 27:1)
Peter's Statement would be the Clearest Teaching of OSAS in the Bible, if only it were true!!!
Notice that he said:
"Peter replied, “Even if all fall away on account of you, I never will.” (Mat 26:33)
1. From this statement, we learn, the Apostles who had walked with Christ, for 3 years, and were all (apart from Judas, where it is debatable whether he was ever justified or not) undoubtedly justified, considered it possible for all to fall away.
2. The one who personally confidently boasts/states that he will not fall away, will often, sadly, when trials/tribulation/persecution comes, be the first to fall. Hence no one should say, "Even if you fall, I never will, for sure".
3. God is Sovereign over life and death and does not allow His elect who are predestined not only to grace but also to glory (i.e. who receive Justification, Sanctification and Perseverance) to die in deadly/grave/mortal sin.
4. St. Peter the Apostle, in his Later Epistle, now clearly teaches people can fall away from Christ, in such a way that the latter state is worse than the beginning. He says apostates are worse than those who have never known Christ. Hence, it follows that as those who have never known Christ are lost, so also those who knowingly apostatized and then remained unrepentant until death are also lost. imo, this statement suggests Judas was probably once justified but later apostate.
5. Here is the passage:
"20If indeed they have escaped the corruption of the world through the knowledge of our Lord and Savior Jesus Christ,f only to be entangled and overcome by it again, their final condition is worse than it was at first. 21It would have been better for them not to have known the way of righteousness than to have known it and then to turn away from the holy commandment passed on to them. 22Of them the proverbs are true: “A dog returns to its vomit,”g and, “A sow that is washed goes back to her wallowing in the mud.” (2 Pet 2).
From this passage, we learn 2 things (1) after being really washed/justified, we can fall away. (2) those who do that are worse than those who never knew the way of righteousness. In other words, apostates who die unrepentant suffer more in hell than unbelievers who never knew the Gospel. It is a sad Truth, but it is Truth. In Hebrews also, it says a similar thing.
God Bless.