It is in man’s heart–his innermost being–where sin is conceived. It was in Satan’s heart
that sin originated. His “heart” was lifted up because of his beauty (Ezekiel 28:17). It was
in his “heart” that he exalted himself above God (Isaiah 14:13-14). The sin of Ananias
and Sapphira originated in their hearts (Acts 5:3).
The Greek word for "heart" is kardia, which includes man’s entire mental and moral
activity–the inner man. The heart and mind are linked and are where the emotions,
desires, perceptions, thoughts, understanding, reasoning powers, conscience, intentions,
will, and imagination reside.
What is in a man’s heart and mind determines what he is. “For as he thinketh in his
heart, so is he” (Proverbs 23:7). Jesus told the Pharisees:
Oh generation of vipers, how can ye, being evil, speak good things? For out of the
abundance of the heart the mouth speaketh. A good man out of the good treasure
of the heart bringeth forth good things: and an evil man out of the evil treasure
bringeth forth evil things. (Matthew 12:34-35)
These verses reveal that man’s heart is where either good or evil resides. Your words and
actions are determined by what is in your heart, and your heart is affected by your
thought life. If there is hatred, anger, jealousy, and pride in your mind, these negative
emotions will affect your heart and be manifested in the words that come out of your
mouth and in your actions.
The heart is the center of your existence. It is in your heart that you receive the Word, are
convicted by the Holy Spirit, and receive salvation (Romans 10:8-10). It is in the heart–
within your innermost being–where you either have faith to believe God’s Word or you
harbor doubt and unbelief that will hinder you from claiming God's promises. Jesus said,
“Have faith in God. Truly I say to you, whoever says to this mountain, ‘Be taken up and
cast into the sea,’ and does not doubt in his heart, but believes that what he says is going
to happen it shall be granted him” (Mark 11:22-23, NAS).
Because the heart and mind are so closely related, we must look at what God’s Word says
concerning them in order to have a clear understanding of this major battlefield. The
Greek word used to refer to the mind is nous, which is used to describe the mental
functions of perception, understanding, knowing, feeling, judging, and determining. The
mind is comprised of the will, emotions, thoughts, and imagination which influence the
issues of your heart. Are you beginning to see why this is the most important spiritual
battlefield?