Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God…. (Hebrews 3:12-15 ESV)
Therefore let us leave the elementary doctrine of Christ and go on to maturity, not laying again a foundation of repentance from dead works and of faith toward God, and of instruction about washings, the laying on of hands, the resurrection of the dead, and eternal judgment. And this we will do if God permits. For it is impossible, in the case of those who have once been enlightened, who have tasted the heavenly gift, and have shared in the Holy Spirit, and have tasted the goodness of the word of God and the powers of the age to come, and then have fallen away, to restore them again to repentance, since they are crucifying once again the Son of God to their own harm and holding him up to contempt…. (Hebrews 6:1-8 ESV)
For if we go on sinning deliberately after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a fearful expectation of judgment, and a fury of fire that will consume the adversaries.… (Hebrews 10:26-31 ESV)
We can’t say that it’ll never happen here; it’ll never happen to me. The writer to the Hebrews uses four different opportunities to warn his readers. All four cautions are really one in the same: Christians who have heard and “accepted” the gospel may turn away from the One true God and His truth into apostasy (unbelief and rejection of Christ). This warning is put here for you and for me.
Don’t tell me you’ve got it all under control as you walk away from an intimate walk with God and the fellowship of believers. You’re a train wreck waiting to happen. Take care that you don’t spurn the Son of God and profane the blood of the covenant by which he was sanctified and outrage the Spirit of grace (see Hebrews 10:29). Draw near to God, hold fast to the confession of our hope, and keep meeting together so that you can stir up love and good deeds among yourselves.