'Harden' in the Bible

so, then, to whom He willeth, He doth kindness, and to whom He willeth, He doth harden.

Harden not your hearts, as in the provocation, in the day of temptation in the wilderness:

While it is said, To day if ye will hear his voice, harden not your hearts, as in the provocation.

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.