إِلاَّ مَن تَابَ وَامَنَ وَعَمِلَ عَمَلً صَالِحًا
Except those who repent and believe, and do righteous deeds;
means, those who do these evil deeds will be punished in the manner described,
إِلاَّ مَن تَابَ
(Except those who repent),
that is; those who repent in this world to Allah from all of those deeds, for then Allah will accept their repentance. This is evidence that the repentance of the murderer is acceptable, and there is no contradiction between this and the Ayah in Surah An-Nisa';
وَمَن يَقْتُلْ مُوْمِناً مُّتَعَمِّداً
And whoever kills a believer intentionally, (4;93)
because even though this was revealed in Al-Madinah, the meaning is general, and it could be interpreted to refer to one who does not repent, because this Ayah states that forgiveness is only for those who repent.
Moreover Allah says;
إِنَّ اللَّهَ لَا يَغْفِرُ أَن يُشْرَكَ بِهِ وَيَغْفِرُ مَا دُونَ ذَلِكَ لِمَن يَشَأءُ
Verily, Allah forgives not that partners should be set up with Him, but He forgives except that to whom He wills. (4;48)
And in the authentic Sunnah, it is reported from the Messenger of Allah that the repentance of a murderer is acceptable, as was stated in the story of the person who killed one hundred men and then repented, and Allah accepted his repentance, and other Hadiths.
فَأُوْلَيِكَ يُبَدِّلُ اللَّهُ سَيِّيَاتِهِمْ حَسَنَاتٍ وَكَانَ اللَّهُ غَفُورًا رَّحِيمًا
for those, Allah will change their sins into good deeds, and Allah is Oft-Forgiving, Most Merciful.
Imam Ahmad recorded that Abu Dharr, may Allah be pleased with him, said,
"The Messenger of Allah said;
إِنِّي لَاَعْرِفُ اخِرَ أَهْلِ النَّارِ خُرُوجًا مِنَ النَّارِ وَاخِرَ أَهْلِ الْجَنَّةِ دُخُولاً إِلَى الْجَنَّةِ يُوْتَى بِرَجُلٍ فَيَقُولُ نَحُّوا عَنْهُ كِبَارَ ذُنُوبِهِ وَسَلُوهُ عَنْ صِغَارِهَا قَالَ فَيُقَالُ لَهُ عَمِلْتَ يَوْمَ كَذَا كَذَا وَكَذَا وَعَمِلْتَ يَوْمَ كَذَا كَذَا وَكَذَا فَيَقُولُ نَعَمْ لَا يَسْتَطِيعُ أَنْ يُنْكِرَ مِنْ ذَلِكَ شَيْيًا فَيُقَالُ فَإِنَّ لَكَ بِكُلِّ سَيِّيَةٍ حَسَنَةً فَيَقُولُ يَا رَبِّ عَمِلْتُ أَشْيَاءَ لَا أَرَاهَا ههُنَا
I know the last person who will be brought forth from Hell, and the last person who will enter Paradise. A man will be brought and it will be said,
"Take away his major sins and ask him about his minor sins."
So it will be said to him;"On such and such a day, you did such and such, and on such and such a day, you did such and such."
He will say, "Yes, and he will not be able to deny anything."
Then it will be said to him;"For every evil deed you now have one good merit."
He will say;"O Lord, I did things that I do not see here."
He (Abu Dharr) said;
"And the Messenger of Allah smiled so broadly that his molars could be seen."
Muslim recorded it.
Ibn Abi Hatim recorded that Abu Jabir heard Makhul say,
"A very old man with sunken eyes came and said, `O Messenger of Allah, a man betrayed others and did immoral deeds, and there was no evil deed which he did not do. If (his sins) were to be distributed among the whole of mankind, they would all be doomed. Is there any repentance for him?"
The Messenger of Allah said;
Have you become Muslim?
He said, "As for me, I bear witness that there is no God but Allah Alone, with no partner or associate, and that Muhammad is His servant and Messenger."
The Prophet said;
فَإِنَّ اللهَ غَافِرٌ لَكَ مَا كُنْتَ كَذَلِكَ وَمُبَدِّلُ سَيِّيَاتِكَ حَسَنَات
Allah will forgive you for whatever you have done like that, and will replace your evil deeds with good merits.
The man said;"O Messenger of Allah, even my betrayals and immoral actions?"
The Prophet said;
Even your betrayals and immoral actions.
"The man went away saying `La ilaha illallah' and `Allahu Akbar."'
Allah tells us how His mercy extends to all His creatures, and that whoever among them repents to Him, He will accept his repentance for any sin, great or small.
وَمَن تَابَ وَعَمِلَ صَالِحًا فَإِنَّهُ يَتُوبُ إِلَى اللَّهِ مَتَابًا