Allah, the Exalted, says:
"And ask forgiveness for your sin...'' (47:19)
"And seek the forgiveness of Allah. Certainly, Allah is Ever Oft-Forgiving, Most Merciful.'' (4:106)
"And declare the freedom of your Rubb from imperfection beginning with His praise, and ask His forgiveness. Verily, He is the One Who accepts the repentance and Who forgives.'' (110:3)
"For Al-Muttaqun (the pious) there are Gardens (Jannah) with their Rubb, underneath which rivers flow. Therein (is their) eternal (home) and Azwajun Mutahharatun (purified mates or wives). And Allah will be pleased with them. And Allah is All-Seer of the (His) slaves. Those who say: `Our Rubb! We have indeed believed, so forgive us our sins and save us from the punishment of the Fire. (They are) those who are patient, those who are true (in Faith, words, and deeds), and obedient with sincere devotion in worship to Allah. Those who spend (give the Zakat and alms in the way of Allah) and those who pray and beg Allah's Pardon in the last hours of the night.'' (3:15-17)
"And whoever does evil or wrongs himself but afterwards seeks Allah's forgiveness, he will find Allah Oft-Forgiving, Most Merciful.'' (4:110)
"And Allah would not punish them while you (Muhammad (PBUH)) are amongst them, nor will He punish them while they seek (Allah's) forgiveness.'' (8:33)
"And those who, when they have committed Fahishah (illegal sexual intercourse) or wronged themselves with evil, remember Allah and ask forgiveness for their sins; - and none can forgive sins but Allah - and do not persist in what (wrong) they have done, while they know.'' (3:135)
1871. Abu Hurairah (May Allah be pleased with him) said: The Messenger of Allah (PBUH) said, "By the One in Whose Hand my soul is! If you do not commit sins, Allah would replace you with a people who would commit sins and seek forgiveness from Allah; and Allah will certainly forgive them.''
[Muslim].
http://www.witness-p ioneer.org/vil/hadee th/riyad/19/chap371. htm
