The allusion for the story “Harden your Heart” in the bible is about a careless heart. The allusion is that a hardened heart does not feel compassion. It is related to the bible because in the story of the hardened heart, the pharaoh does not let the Israelites go. Th\is shows that he has a heart of stone, and does not show empathy for others. The allusion occurs in Exodus 9:12 when it says “But The lord Hardened the heart of the pharaoh...”and in Ephesians 4:18 “They are darkened in their understanding, alienated from the life of God because of the ignorance that is in them, due to their hardness of heart.” This allusion is represented as a serious matter, it shows that someone is careless or doesn't respect another person or thing. The richness of this allusion is supposed to be a hurtful thing, the phrase is telling the person that they have a stone heart that cares for no one. That is the allusion of “Harden Your Heart”.

I also found a book called Idolatry and the Hardening of the Heart and a music composition called Harden my Heart by Quarterflash. And an article called Harden your heart 

see here: http://www.psychologytoday.com/articles/200402/dont-harden-your-heart