Unbelief is but one, the other is blasphemy of the Holy Spirit:
31:And so I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven. 32:Anyone who speaks a word against the Son of Man will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come.
That is contributing the works of the Holy Spirit to Satan. Even a believer that uses the Lord's name in vain can be forgiven.
Also, for those that use their OSAS as an excuse to sin:
Matthew 7: 21-23
21 “Not everyone who says to Me, ‘Lord, Lord,’ shall enter the kingdom of heaven, but he who does the will of My Father in heaven. 22 Many will say to Me in that day, ‘Lord, Lord, have we not prophesied in Your name, cast out demons in Your name, and done many wonders in Your name?’ 23 And then I will declare to them, ‘I never knew you; depart from Me, you who practice lawlessness!’
If you are gonna talk the talk, you need to walk the walk. We always are acting against human nature trying to live a life that we would want Jesus to approve of, and we never will be able to. That doesn't mean you don't try, and when you fail, repent, and try again. The idea is not to live your life for yourself, but to prepare your life so that Jesus may live his life through you.
CHIEF