Hebrews 3:15
So while we can still speak of Today, if you hear him speak, do not harden your hearts, as they provoked him by doing.
Hebrews 3:7-8
Therefore, as the holy Spirit says, "If you hear his voice today,
Hebrews 10:29
How much worse a punishment do you think will anyone deserve who tramples the Son of God underfoot, and treats as worthless the blood of the agreement by which he has been purified, and outrages God's spirit of mercy?
Hebrews 10:38
And he whom I accept as righteous will find life through his faith. But if a man draws back, my heart can take no pleasure in him."
Treasury of Scripture Knowledge
Summary
While it is said, To day if ye will hear his voice, harden not your hearts, as in the provocation.