If we refuse or neglect to confess our sinful behavior with a heart of repentance,
but deny, excuse, blameshift, or downplay the unrighteousness and guiltiness of our sin,
we are by definition hardening our heart in rebellion against the Lord our God.
Proverbs 28:13-14
He that covereth his sins shall not prosper:
but whoso confesseth and forsaketh them shall have mercy.
Happy is the man that feareth alway:
but he that hardeneth his heart shall fall into mischief.
Jeremiah 18:11-12
Now therefore go to, speak to the men of Judah, and to the inhabitants of Jerusalem, saying, Thus saith the LORD; Behold, I frame evil against you, and devise a device against you:
return ye now every one from his evil way, and make your ways and your doings good.
And they said, There is no hope: but we will walk after our own devices,
and we will every one do the imagination of his evil heart.
Proverbs 29:1
He, that being often reproved hardeneth his neck,
shall suddenly be destroyed, and that without remedy.
Romans 2:4
Or despisest thou the riches of his goodness and forbearance and longsuffering;
not knowing that the goodness of God leadeth thee to repentance?