About encouragement and advice to repentance, the Qur'an speaks:
إِنَّ ٱللَّهَ يُحِبُّ ٱلتَّوَّٰبِينَ وَيُحِبُّ ٱلۡمُتَطَهِّرِينَ
"Surely Allah loves those who repentance and loves those who purify themselves." (Al-Baqarah: 222).
So what is the higher degree than affection of Allah, the God of the Worlds. In telling about ibadurrahman that Allah gave glory to attribute them to him, and promised them heaven, in which they receive congratulations word and remained there, as well as get a good place. The Word of Allah:
وَٱلَّذِينَ لَا يَدۡعُونَ مَعَ ٱللَّهِ إِلَٰهًا ءَاخَرَ وَلَا يَقۡتُلُونَ ٱلنَّفۡسَ ٱلَّتِي حَرَّمَ ٱللَّهُ إِلَّا بِٱلۡحَقِّ وَلَا يَزۡنُونَۚ وَمَن يَفۡعَلۡ ذَٰلِكَ يَلۡقَ أَثَامٗا . يُضَٰعَفۡ لَهُ ٱلۡعَذَابُ يَوۡمَ ٱلۡقِيَٰمَةِ وَيَخۡلُدۡ فِيهِۦ مُهَانًا . إِلَّا مَن تَابَ وَءَامَنَ وَعَمِلَ عَمَلٗا صَٰلِحٗا فَأُوْلَٰٓئِكَ يُبَدِّلُ ٱللَّهُ سَئَِّاتِهِمۡ حَسَنَٰتٖۗ وَكَانَ ٱللَّهُ غَفُورٗا رَّحِيمٗا
And people who do not call upon another god with Allah and do not slay the soul, which Allah has forbidden except in the requirements of justice, and (who) do not commit fornication and he who does this shall find a requital of sin; The punishment shall be doubled to him on the day of resurrection, and he shall abide therein in abasement; Except him who repentance and believes and does a good deed; so these are they of whom Allah changes the evil deeds to good ones; and Allah is Forgiving, Merciful. (Al Furqaan: 68-70).
And in the explanation about vastness of forgiveness of Allah and His mercy to those who repentance. Allah says:
قُلۡ يَٰعِبَادِيَ ٱلَّذِينَ أَسۡرَفُواْ عَلَىٰٓ أَنفُسِهِمۡ لَا تَقۡنَطُواْ مِن رَّحۡمَةِ ٱللَّهِۚ إِنَّ ٱللَّهَ يَغۡفِرُ ٱلذُّنُوبَ جَمِيعًاۚ إِنَّهُۥ هُوَ ٱلۡغَفُورُ ٱلرَّحِيمُ
"Say: 'O My servants who have transgressed against themselves, do not despair of the mercy of God. Indeed, Allah forgives all sins. Verily He is the Oft-Forgiving, Most Merciful. "(Qur'an, Az-Zumar: 53)
This meaning of verse above is Allah opened the door with the widest for all sinners and performs error. Although the sin they have reached the end of the sky though. Like the words of the Prophet:
"If you make mistakes (sins) to be your fault it up to the sky, then you repentance, Allah will give repentance to you." (Hadith narrated by Ibn Majjah from Abu Hurayrah, hasan hadeeth valid in the sahih book of Jami 'Shagir)
The virtue of those who repentance are: Allah commissioned Muqarrabi angels to say says istighfar for them and pray to Allah so that Allah save them from the punishment of hell. As well as incorporating them into heaven. And save them from evil. They think of them affairs in the world, while the angels busy with their in the sky.
Allah says in Quran:
ٱلَّذِينَ يَحۡمِلُونَ ٱلۡعَرۡشَ وَمَنۡ حَوۡلَهُۥ يُسَبِّحُونَ بِحَمۡدِ رَبِّهِمۡ وَيُؤۡمِنُونَ بِهِۦ وَيَسۡتَغۡفِرُونَ لِلَّذِينَ ءَامَنُواْۖ رَبَّنَا وَسِعۡتَ كُلَّ شَيۡءٖ رَّحۡمَةٗ وَعِلۡمٗا فَٱغۡفِرۡ لِلَّذِينَ تَابُواْ وَٱتَّبَعُواْ سَبِيلَكَ وَقِهِمۡ عَذَابَ ٱلۡجَحِيمِ. رَبَّنَا وَأَدۡخِلۡهُمۡ جَنَّٰتِ عَدۡنٍ ٱلَّتِي وَعَدتَّهُمۡ وَمَن صَلَحَ مِنۡ ءَابَآئِهِمۡ وَأَزۡوَٰجِهِمۡ وَذُرِّيَّٰتِهِمۡۚ إِنَّكَ أَنتَ ٱلۡعَزِيزُ ٱلۡحَكِيمُ. وَقِهِمُ ٱلسَّئَِّاتِۚ وَمَن تَقِ ٱلسَّئَِّاتِ يَوۡمَئِذٖ فَقَدۡ رَحِمۡتَهُۥۚ وَذَٰلِكَ هُوَ ٱلۡفَوۡزُ ٱلۡعَظِيمُ
Those who bear the power and those around Him celebrate the praise of their Lord and believe in Him and ask protection for those who believe: Our Lord! Thou embracest all things in mercy and knowledge, therefore grant protection to those who turn (to Thee) and follow Thy way, and save them from the punishment of the hell: Our Lord! and make them enter the gardens of perpetuity which Thou hast promised to them and those who do good of their fathers and their wives and their offspring, surely Thou are the Mighty, the Wise. And keep them from evil deeds, and whom Thou keepest from evil deeds this day, indeed Thou hast mercy on him, and that is the mighty achievement. Quran. Ghaafir: 7-9).
There are many verses in the Qur'an that describe that people who repentance would be receive if they repentance sincerely, with many editors. With the postulate on the mercy of the gift of Allah, forgiveness and mercy, that does not feel cramped with people who do immoral acts, even though they immoral had been so great.
As in the word of Allah:
أَلَمۡ يَعۡلَمُوٓاْ أَنَّ ٱللَّهَ هُوَ يَقۡبَلُ ٱلتَّوۡبَةَ عَنۡ عِبَادِهِۦ وَيَأۡخُذُ ٱلصَّدَقَٰتِ وَأَنَّ ٱللَّهَ هُوَ ٱلتَّوَّابُ ٱلرَّحِيمُ
Do they not know that Allah accepts repentance from His servants and takes the alms, and that Allah is the Oft-returning (to mercy), the Merciful? (Quran. At-Taubah: 104)
وَهُوَ ٱلَّذِي يَقۡبَلُ ٱلتَّوۡبَةَ عَنۡ عِبَادِهِۦ وَيَعۡفُواْ عَنِ ٱلسَّئَِّاتِ وَيَعۡلَمُ مَا تَفۡعَلُونَ
And He it is Who accepts repentance from His servants and pardons the evil deeds and He knows what you do; (Quran. Asy-Syuuraa: 25)
غَافِرِ ٱلذَّنۢبِ وَقَابِلِ ٱلتَّوۡبِ شَدِيدِ ٱلۡعِقَابِ ذِي ٱلطَّوۡلِۖ لَآ إِلَٰهَ إِلَّا هُوَۖ إِلَيۡهِ ٱلۡمَصِيرُ
The Forgiver of the faults and the Acceptor of repentance, Severe to punish, Lord of bounty; there is no god but He; to Him is the eventual coming. (Quran. Ghaafir: 3)
Especially those who repentance and make improvements. Or in other words, those who repentance and do righteous deeds. As in the word of Allah in matters of men and women who steal:
فَمَن تَابَ مِنۢ بَعۡدِ ظُلۡمِهِۦ وَأَصۡلَحَ فَإِنَّ ٱللَّهَ يَتُوبُ عَلَيۡهِۚ إِنَّ ٱللَّهَ غَفُورٞ رَّحِيمٌ
So whoever repents after his iniquity and reforms (himself), then surely Allah will turn to him (mercifully); surely Allah is Forgiving, Merciful. Quran. Al Maaidah: 39)
وَإِذَا جَآءَكَ ٱلَّذِينَ يُؤۡمِنُونَ بَِٔايَٰتِنَا فَقُلۡ سَلَٰمٌ عَلَيۡكُمۡۖ كَتَبَ رَبُّكُمۡ عَلَىٰ نَفۡسِهِ ٱلرَّحۡمَةَ أَنَّهُۥ مَنۡ عَمِلَ مِنكُمۡ سُوٓءَۢا بِجَهَٰلَةٖ ثُمَّ تَابَ مِنۢ بَعۡدِهِۦ وَأَصۡلَحَ فَأَنَّهُۥ غَفُورٞ رَّحِيمٞ
And when those who believe in Our communications come to you, say: Peace be on you, your Lord has ordained mercy on Himself, (so) that if any one of you does evil in ignorance, then turns after that and acts aright, then He is Forgiving, Merciful. (Quran. Al An'aam: 54)
ثُمَّ إِنَّ رَبَّكَ لِلَّذِينَ عَمِلُواْ ٱلسُّوٓءَ بِجَهَٰلَةٖ ثُمَّ تَابُواْ مِنۢ بَعۡدِ ذَٰلِكَ وَأَصۡلَحُوٓاْ إِنَّ رَبَّكَ مِنۢ بَعۡدِهَا لَغَفُورٞ رَّحِيمٌ
Yet surely your Lord, with respect to those who do an evil in ignorance, then turn after that and make amends, most surely your Lord after that is Forgiving, Merciful. (Quran. An-Nahl: 119)
Praise to Allah with his name "at-Tawwab" (oft Taubat) contained in the Quran as much as eleven places. As in the prayer of Ibrahim and Isma'il U.S.:
رَبَّنَا وَٱجۡعَلۡنَا مُسۡلِمَيۡنِ لَكَ وَمِن ذُرِّيَّتِنَآ أُمَّةٗ مُّسۡلِمَةٗ لَّكَ وَأَرِنَا مَنَاسِكَنَا وَتُبۡ عَلَيۡنَآۖ إِنَّكَ أَنتَ ٱلتَّوَّابُ ٱلرَّحِيمُ
Our Lord! and make us both submissive to Thee and (raise) from our offspring a nation submitting to Thee, and show us our ways of devotion and turn to us (mercifully), surely Thou art the Oft-returning (to mercy), the Merciful. (Quran. Al-Baqarah: 128).
An also in the words of Moses to the Children of Israel after they worshiped the calf:
وَإِذۡ قَالَ مُوسَىٰ لِقَوۡمِهِۦ يَٰقَوۡمِ إِنَّكُمۡ ظَلَمۡتُمۡ أَنفُسَكُم بِٱتِّخَاذِكُمُ ٱلۡعِجۡلَ فَتُوبُوٓاْ إِلَىٰ بَارِئِكُمۡ فَٱقۡتُلُوٓاْ أَنفُسَكُمۡ ذَٰلِكُمۡ خَيۡرٞ لَّكُمۡ عِندَ بَارِئِكُمۡ فَتَابَ عَلَيۡكُمۡۚ إِنَّهُۥ هُوَ ٱلتَّوَّابُ ٱلرَّحِيمُ
And when Musa said to his people: O my people! you have surely been unjust to yourselves by taking the calf (for a god), therefore turn to your Creator (penitently), so kill your people, that is best for you with your Creator: so He turned to you (mercifully), for surely He is the Oft-returning (to mercy), the Merciful. (Quran. Al Baqarah: 54)
Allah says to His Messenger:
وَمَآ أَرۡسَلۡنَا مِن رَّسُولٍ إِلَّا لِيُطَاعَ بِإِذۡنِ ٱللَّهِۚ وَلَوۡ أَنَّهُمۡ إِذ ظَّلَمُوٓاْ أَنفُسَهُمۡ جَآءُوكَ فَٱسۡتَغۡفَرُواْ ٱللَّهَ وَٱسۡتَغۡفَرَ لَهُمُ ٱلرَّسُولُ لَوَجَدُواْ ٱللَّهَ تَوَّابٗا رَّحِيمٗا
And We did not send any messenger but that he should be obeyed by Allah´s permission; and had they, when they were unjust to themselves, come to you and asked forgiveness of Allah and the Messenger had (also) asked forgiveness for them, they would have found Allah Oft-returning (to mercy), Merciful. (Quran. An-Nisa: 64)