Keep Your Heart With All Diligence

Keep your heart with all diligence, For out of it spring the issues of life. (Proverbs 4:23 NKJ)

For the word of God is living and powerful, and sharper than any two-edged sword, piercing even to the division of soul and spirit, and of joints and marrow, and is a discerner of the thoughts and intents of the heart. (Hebrews 4:12 NKJ)

Let the words of my mouth and the meditation of my heart be acceptable in Your sight, O LORD, my strength and my Redeemer. (Psalm 19:14 NKJ)

Most people think the heart has something to do with the emotions or the passions.  However, in both the New Testament and in the Old Testament the word for heart has more to do with thinking and the rational soul than with passions or emotions, although it is used in that regard at times.  In Hebrew the word for "heart" is "leb."  (Pronounced "labe").  

Click here to see the Interlinear Hebrew verse:   Biblos Interlinear.  Remember that Hebrew reads from right to left.   The Enhanced Strong's Concordance and Lexicon says:

leb: inner man, mind, will, heart

Original Word: לֵב

Meaning:  1) inner man, mind, will, heart, understanding 1a) inner part, midst 1a1) midst (of things) 1a2) heart (of man) 1a3) soul, heart (of man) 1a4) mind, knowledge, thinking, reflection, memory 1a5) inclination, resolution, determination (of will) 1a6) conscience 1a7) heart (of moral character) 1a8) as seat of appetites 1a9) as seat of emotions and passions 1a10) as seat of courage
Origin:  a form of 03824; TWOT - 1071a; n m

Usage:  AV - heart 508, mind 12, midst 11, understanding 10, hearted 7, wisdom 6, comfortably 4, well 4, considered 2, friendly 2, kindly 2, stouthearted + 047 2, care + 07760 2, misc 20; 592

Click here to see the Brown Driver Briggs Hebrew Lexicon definitions:  BDB:  Leb.

My challenge to you is to go through the Bible and read all the instances in the OT and NT where the word "heart" is used and see the context.  In the majority of instances the reference has to do with mind or thinking.  Proverbs 23:7 is a good example of that.

Even in the New Testament Jesus says that premeditations of the "heart" result in sinful actions:

"For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies. (Matthew 15:19 NKJ)

See the interlinear verse here:  Biblos Interlinear.

Notice the Strong's definition again: 

2588 καρδία, ας, ἡ
Meaning:  1) the heart 1a) that organ in the animal body which is the centre of the circulation of the blood, and hence was regarded as the seat of physical life 1b) denotes the centre of all physical and spiritual life 2a) the vigour and sense of physical life 2b) the centre and seat of spiritual life 2b1) the soul or mind, as it is the fountain and seat of the thoughts, passions, desires, appetites, affections, purposes, endeavours 2b2) of the understanding, the faculty and seat of the intelligence 2b3) of the will and character 2b4) of the soul so far as it is affected and stirred in a bad way or good, or of the soul as the seat of the sensibilities, affections, emotions, desires, appetites, passions 1c) of the middle or central or inmost part of anything, even though inanimate

Origin:  prolonged from a primary kar (Latin, cor, "heart"); TDNT - 3:605,415; n f
Usage:  AV - heart 159, broken hearted + 4937 1; 160

Although the word for heart in Scripture can refer to the emotions or passions, in the vast majority of cases it refers to the thoughts and intents of  the "mind" (Hebrews 4:12).  The Bible makes no distinction between "head knowledge" and "heart knowledge."  In the Bible the heart refers to the soul, which in modern terminology would include the intellect or "head knowledge."   The anti-intellectualist bent of most Evangelicals today is therefore unscriptural.

But his delight is in the law of the LORD, And in His law he meditates day and night. (Psalm 1:2 NKJ)

Your word I have hidden in my heart, That I might not sin against You! (Psalm 119:11 NKJ) 

NUN. Your word is a lamp to my feet And a light to my path. (Psalm 119:105 NKJ)