On the authority of Anas, who said: 
I heard the messenger of Allah say:

Allah the Almighty has said: 

O son of Adam
So long as you call upon Me and ask of Me 
I shall forgive you for what you have done 
And I shall not mind 

O son of Adam 
Were your sins to reach the clouds of the sky 
And were you then to ask forgiveness of Me 
I would forgive you 

O son of Adam 
Were you to come to Me with sins nearly as great as the earth 
And were you then to face Me 
Ascribing no partner to Me 
I would bring you forgiveness nearly as great as its