Genesis 6:5
5 Then the LORD saw that the wickedness of man was great on the earth, and that every intent of the thoughts of his heart was only evil continually.
NAS
Genesis 8:21
21 And the LORD smelled the soothing aroma; and the LORD said to Himself, "I will never again curse the ground on account of man, for the intent of man's heart is evil from his youth; and I will never again destroy every living thing, as I have done. NAS
God will forgive those who repent of and confess their sins. However, God will not forgive the sins of those who do not repent.