Yet Hebrews 3:12-13 says: "See to it, brothers, that none of you has a sinful, unbelieving heart that turns away from the living God. But encourage one another daily, as long as it is called Today, so that none of you may be hardened by sin's deceitfulness."
A sinful, unbelieving heart that turns away from God is one that is full of pride. And as C.S. Lewis wrote in "The Great Sin" chapter in Mere Christianity, "As long as you are proud you cannot know God." (This whole chapter is brilliant and every word is applicable to these verses from Hebrews!)
So what's the solution to this, unbelieving, prideful, "anti-God state of mind"? It's acknowledging our own sin. We need to pray for discernment to see where we are out of God's will, and we need to read and meditate on God's Word.
Lewis closes his chapter with the following:
If anyone would like to acquire humility, I can, I think tell him the first step. The first step is to realise that one is proud. And a biggish step, too. At least, nothing whatever can be done before it. If you think you are not conceited, it means you are very conceited indeed.
So, friend, "it is called Today," may we encourage one another and not be deceived by the hardening work of sin. May we, through the power of the Holy Spirit, choose to believe, to trust and to obey.