Perhaps looking intently at the old heart would lift the fog and help you understand why a new heart is promised and necessary under the New Covenant:
Gen 6:5
5 Then the Lord saw that the wickedness of man was great on the earth, and that every intent of the thoughts of his heart was only evil continually
Gen 8:21
21 And the Lord smelled the soothing aroma; and the Lord said to Himself, "I will never again curse the ground on account of man, for the intent of man's heart is evil from his youth; and I will never again destroy every living thing, as I have done.
Jer 17:9
9 "The heart is more deceitful than all else
And is desperately sick;
Who can understand it?
NAS
Matt 9:4
4 Knowing their thoughts, Jesus said, "Why do you entertain evil thoughts in your hearts?
NIV
Mark 7:21-23
21 "For from within, out of the heart of men, proceed the evil thoughts, fornications, thefts, murders, adulteries, 22 deeds of coveting and wickedness, as well as deceit, sensuality, envy, slander, pride and foolishness. 23 "All these evil things proceed from within and defile the man."
NASB
Prov 28:26
26 He who trusts in his own heart is a fool,
But he who walks wisely will be delivered.
NAS