Hardening is like a callus or like the tough bone fibers that bridge a fracture. Spiritual hardening begins with self-sufficiency, security in one’s self, and self-satisfaction. The real danger is that at some point, repeated resistance to God will yield an actual inability to respond, which the Bible describes as a hardened heart. Insensitivity indicates advanced hardening. Here are some of the warning signs:
| Warning Sign | Reference |
| Disobeying—Pharaoh’s willful disobedience led to his hardened heart. | Exodus 4:21 |
| Having wealth and prosperity—Taking God’s blessings for granted can cause us to feel as if they were owed to us. | Deuteronomy 8:6-14 |
| Rebelling and being discontented—Suffering or discomfort can create an attitude that blames God. | Psalm 95:8 |
| Rejecting a deserved rebuke—Rejecting God’s gift makes our neck stiff and our heart hard. | Proverbs 29:1 |
| Refusing to listen—Refusing to listen leads to a loss of spiritual hearing. | Zechariah 7:11-13 |
| Failing to respond—Listening to God with no intention of obeying produces an inability to obey. | Matthew 13:11-15 |