But Christ is faithful as the Son over God’s house. And we are his house, if indeed we hold firmly to our confidence and the hope in which we glory. So, as the Holy Spirit says: “Today, if you hear his voice, do not harden your hearts, as you did in the rebellion during the time of testing in the wilderness, where your ancestors tested and tried me, though for forty years they saw what I did. That is why I was angry with that generation; I said, ‘Their hearts are always going astray, and they have not known my ways.’ So I declared on oath in my anger, ‘They shall never enter my rest.’ ” See to it, brothers and sisters, 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. We have come to share in Christ, if indeed we hold our original conviction firmly to the very end. As has just been said: “Today, if you hear his voice, do not harden your hearts as you did in the rebellion.”
If you do not respond today your heart will grow harder
Blessed is the one who always trembles before God, but whoever hardens their heart falls into trouble.