God in His infinite wisdom created the physical heart as the center of physical life, as it pumps it literally pumps life through your body. So the heart is the term God uses to describe the innermost part of our being from which flows our thoughts, emotions, will, and understanding; those things that actually determine character. It is no wonder that God tells us in Proverbs 4:23 to “Keep thy heart with all diligence; for out of it are the issues of life”!
There are many conditions that affect the spiritual heart and therefore affect our relationship and fellowship with God because He is the only one who can and will judge the thoughts and intents of the heart. Of all those spiritual heart conditions, the worst is the condition of a heart that is full of pride.
Proverbs 16:4-5 The LORD hath made all things for himself: yea, even the wicked for the day of evil. Every one that is proud in heart is an abomination to the LORD: though hand join in hand, he shall not be unpunished.
Proverbs 21:4 An high look, and a proud heart, and the plowing of the wicked, is sin.
The reason it is the worst condition is that a person with a proud heart will not admit they are wrong and need to change. They will not humble themselves, confess their sin to God and repent. They will not ask forgiveness and receive salvation. Twice in Luke 13 Jesus told the people, “Except ye repent ye shall all likewise perish.”