What is the biblical basis for the forgiveness of sins for very evil persons?

This is not that hard of a question to answer, but before properly doing so we must correct the English translation of Jesus' words.

In the English we are told that Jesus stated to "repent", but the English word repent is mainly to feel sorry for ones actions, while the word Jesus used, means: "to exercise the mind" "accompanying" (Reference is the Strong's concordance for the Greek word (μετανοέω metanoeō met-an-o-eh'-o) translated "repent") the new thinking being taught. It actually has nothing to do with feelings, but strictly has to do with a change of thinking and thus then actions.

Jesus came out of the wilderness teachings the gospel of the kingdom, that message was taught in his teachings of loving your enemies, doing good to those who hate you, etc. He wasn't going around and saying repent, without telling them what to do. Jesus' teachings are his message of what to do and they are what he was telling them to exercise their minds towards and accompany them in the lives they live.

So to answer your question: repentance has nothing to do with feelings sorry for your actions, but rather it has to do with changing your thinking and actions and it is on this bases that forgiveness is taught to be granted by Jesus in his teachings.

Blasphemy against the Holy Spirit. Someone above mentioned backsliding but I disagree with that because there are biblical precedents when backsliders were forgiven, Peter being a prime example. It is stated in the Bible that "though righteous fall seven times, they rise again..." Proverbs 24:16 Also sinning unto death (one getting to die with unrepented sin), as mentioned in 1 John 5:16, is unforgiven. That is why praying for the dead who died unrepetant that God may have mercy on then is a terrible deception from the throne of Satan.

There are many instances where Evil persons are forgiven. The important thing is not to confess, but to sincerely confess.

Psalm 51:17 "The sacrifices of God are a broken spirit: a broken and a contrite heart, O God, thou wilt not despise"

So, if Hitler was to ask for fogiveness with a contrite heart and a broken spirit he would be forgiven. Seeing how his last actions were to kill himself and his wife I'm thinking there is a very strong possibility that his heart towards God had not changed. One Charectoristic of the human soul is it tends not to alter it's perceptions and form its beliefs which are rarely altered. My priest mentions often that even at the point of death many people he encounters at the moment of death, even then, do not change there veiws or belief, or repent of their seperation from Grace.

It would be wrong to wish anyone the permenant seperation from Gods Love, Even Hitler or ISIS. We like to determine by human means what sins are severe and which ones are not. In our limited view killing millions of people is evil, but the ocassional lie or sexual transgression is not so bad. Is Gods perception of sin a matter of degrees of sin? There is no biblical bases for such a thing, wether you kill millions or take the Lords name in vain, you have sinned against the almighty and you must make right that fault.

It is not as simple as asking for forgiveness. One must have a contrite heart, must have an obedience of faith, must in some manor be baptised by Christ.

The sin that will not be forgiven is the regection of the Grace of God, the heart that is hardened in rejection, that does not seek for God but rebels against it, a person who actually chooses not to be forgiven, This is the sin against the Holy Spirit which cannot be forgiven.

There is a very beautiful answer in the book of Ezekiel:

KJV Ezekiel 18:-

20 The soul that sinneth, it shall die. The son shall not bear the iniquity of the father, neither shall the father bear the iniquity of the son: the righteousness of the righteous shall be upon him, and the wickedness of the wicked shall be upon him.

21 But if the wicked will turn from all his sins that he hath committed, and keep all my statutes, and do that which is lawful and right, he shall surely live, he shall not die.

22 All his transgressions that he hath committed, they shall not be mentioned unto him: in his righteousness that he hath done he shall live.

23 Have I any pleasure at all that the wicked should die? saith the Lord GOD: and not that he should return from his ways, and live?

24 But when the righteous turneth away from his righteousness, and committeth iniquity, and doeth according to all the abominations that the wicked man doeth, shall he live? All his righteousness that he hath done shall not be mentioned: in his trespass that he hath trespassed, and in his sin that he hath sinned, in them shall he die.

26 When a righteous man turneth away from his righteousness, and committeth iniquity, and dieth in them; for his iniquity that he hath done shall he die.

27 Again, when the wicked man turneth away from his wickedness that he hath committed, and doeth that which is lawful and right, he shall save his soul alive.

28 Because he considereth, and turneth away from all his transgressions that he hath committed, he shall surely live, he shall not die.

Then again in John

John 6:37 All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out.

Yes, the bible says that some sins are not forgiven. There are three sins that I know of:

the Blasphemy of the Holy Spirit (Matthew 12:31), which many scholars simply consider to be a lack of saving faith in Jesus;

refusing to forgive, or not valuing the forgiveness offered to you freely (Matthew 6:15); and,

"backsliding" (Hebrews 6:6), which is again, apparently, despising the forgiveness offered by Jesus on the cross.

I remember a story about a famous prison minister (I think it was Chuck ? of the Watergate scandal) who said that he was suprised by the reaction of Christians when he told them that an infamous serial killer (I think it was the Son of Sam) had confessed and become a Christian before his execution. But Christians should remember that we have all sinned, and Jesus' Easter sacrifice is cheapened if it only covers some of the our sins. I know that there is the possibility for murderers (e.g. one of the thieves on the cross next to Jesus) and even mass murderers can be saved, but as with any sin, it is very difficult to become sincere about your sorrow (see post above) if you have expected to use God's forgiveness as an escape clause just before you die. One possible test of sincerity of the deathbed confession is this; if you somehow don't die (e.g. the Governor pardons you), will you change your life?