Proverbs 29:1

He that being often reproved hardeneth his neck, shall suddenly be destroyed, and that without remedy. KJV

When we think of hardening we can’t help but think of Pharaoh and his hard heart recorded in Exodus 4 through Exodus 14. In these chapters, there are no less than three Hebrew words that are translated as hard or harden. The word most often used “Implies his strengthening himself against all fear and alarm, stoutly resisting the warnings and motives urged upon him and the terrors of God’s judgements”. Wilsons Old Testament Word Studies. PG 207

The second word means to be heavy or add weight. It is also used as unable to see or unwilling to listen. (Think Pharisees John 9) The third word means to be hard, harsh, obstinate, or perverse.

In the use of these words, we can see a progression of hardness that goes from bad to worse. We can also see that we are not immune from becoming hard ourselves. Neither was Israel immune from becoming hard.

Psalm 95:8, Harden not your heart as in the provocation, and as in the day of temptation in the wilderness.