Hebrews 4:5-7

And in this place again, If they shall enter into my rest. Seeing therefore it remaineth that some must enter therein, and they to whom it was first preached entered not in because of unbelief: again, he limiteth a certain day, saying in David, To day, after so long a time; as it is said, To day if ye will hear his voice, Harden not your hearts.