The Women - 4:26
Allah wishes to make clear to you these things, and to guide you to the way of those before you, and to reward you for your turning to Him (your repentance). Allah is All-Knowing, All-Wise.
To turn to Allah; to repent and ask for forgiveness:
The Table Spread/5:39
Whoever repents and reforms after this injustice, Allah will accept his return. Surely Allah is Forgiving, Merciful.
The Table Spread/5:74
Will they not turn to Allah and ask forgiveness from Him? Allah is Forgiving, Merciful.
The Repentance/9:117
Allah has accepted the repentance of the Messenger and those who emigrated and those who helped. They followed him at a time of difficulty when some of them almost lost heart. Then He accepted their turning (repentance). He is Most Compassionate towards them, Most Merciful.
The Prohibition/66:4
If you both repent to Allah, your hearts will be turned. And if you support one another against him (the Messenger), Allah is his guardian, and Jibril and the righteous believers and the angels support him.