28 Verily I say unto you, All sins shall be forgiven unto the sons of men, and blasphemies wherewith soever they shall blaspheme:
29 But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation. Mark 3:28-29
These two verses tell us that our sins can be forgiven. Those who speak irreverently about God though may not be forgiven.