Biblically speaking the heart is the seat of all thought and mind function. From the heart, or mind, comes all thoughts and all actions. A cursory reading of the Bible makes it seem like the heart and mind are different parts of the human person. And they may overlap and not be exactly the same thing. But there are enough passages that speak of them being interchangeable that it makes sense for us to begin with thinking of them as synonymous. A few examples might help:
And GOD saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually. Genesis 6:5
Beware that there be not a thought in thy wicked heart, saying, The seventh year, the year of release, is at hand; and thine eye be evil against thy poor brother, and thou givest him nought; and he cry unto the LORD against thee, and it be sin unto thee. Deuteronomy 15:9
And thou, Solomon my son, know thou the God of thy father, and serve him with a perfect heart and with a willing mind: for the LORD searcheth all hearts, and understandeth all the imaginations of the thoughts: if thou seek him, he will be found of thee; but if thou forsake him, he will cast thee off for ever. 1 Chronicles 28:9
O LORD God of Abraham, Isaac, and of Israel, our fathers, keep this for ever in the imagination of the thoughts of the heart of thy people, and prepare their heart unto thee: 1 Chronicles 29:18
Search me, O God, and know my heart: try me, and know my thoughts: 24 And see if there be any wicked way in me, and lead me in the way everlasting. Psalm 139:23-24
O Jerusalem, wash thine heart from wickedness, that thou mayest be saved. How long shall thy vain thoughts lodge within thee? Jeremiah 4:14
And he entered into a ship, and passed over, and came into his own city. 2 And, behold, they brought to him a man sick of the palsy, lying on a bed: and Jesus seeing their faith said unto the sick of the palsy; Son, be of good cheer; thy sins be forgiven thee. 3 And, behold, certain of the scribes said within themselves, This man blasphemeth. 4 And Jesus knowing their thoughts said, Wherefore think ye evil in your hearts? Matthew 9:1-4
For out of the heart proceed evil thoughts, , eries, fornications, thefts, false witness, blasphemies: Matthew 15:19
For from within, out of the heart of men, proceed evil thoughts, eries, fornications, , 22 Thefts, covetousness, wickedness, deceit, lasciviousness, an evil eye, blasphemy, pride, foolishness: 23 All these evil things come from within, and defile the man. Mark 7:21-23
(Yea, a sword shall pierce through thy own soul also,) that the thoughts of many hearts may be revealed. Luke 2:35
And the scribes and the Pharisees began to reason, saying, Who is this which speaketh blasphemies? Who can forgive sins, but God alone? 22 But when Jesus perceived their thoughts, he answering said unto them, What reason ye in your hearts? Luke 5:21-22
(For not the hearers of the law are just before God, but the doers of the law shall be justified. 14 For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves: 15 Which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another;) Romans 2:13-15
For the word of God is quick, and powerful, and sharper than any two edged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart. Hebrews 4:12
Some might argue that Matthew 15:19 and Mark 7:21-23 teach us that there is something different about our thoughts and our hearts because Jesus said “out of the heart” come these kinds of thoughts. But in all these other passages the heart is what is doing the thinking. And so while there might be some things, behaviors for instance, that are not the heart, they come from and spring from the heart, they are generated by the heart.
What I’m saying is that I believe that the heart is the Old Testament version or expression of what the Greek or New Testament folks called the mind. In Deuteronomy 6:4, for example, God told Israel to worship him with all their “heart, soul, and might.” In the New Testament Jesus added the mind (Mt. 22:37; Mk. 12:30; Lk. 10:27). I think this was just in case anyone missed it. The point is that God wants all of us, every fiber of our being. He doesn’t want us to be able to have anything to ourselves.
The heart is the seat of who we are as human beings. It generates our thoughts and our actions. In the New Testament there may be a subtle shift from heart to mind or there may just be a strong over lap between what the writers and readers thought of as the heart and mind. But generally speaking there is no difference between the way the word heart is being used and the way the word mind is being used.
So to ask how a person changes his heart is the same question as how does a person change his mind.
The Bible tells us that only God can see into a person’s heart. But at the same time it repeatedly tells the Israelites to circumcise their hearts. And, in those contexts what God meant was that the Israelites needed to repent. But repent means to change your mind. This again is another indicator that heart and mind are the same part that need to be changed in the person who is in rebellion against God.
How a person changes his heart is something of an enigma. It is similar to how a person is reborn. How do we do it?
Here is one way to think about it:
I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. 2 And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God. Romans 12:1-2
This passage tells us that we are to present our bodies to God as living sacrifices, which is our reasonable service (or worship). And as we do this we will no longer be conformed to the way the world thinks and does things, but instead our minds will be transformed and renewed.
Okay, so I’ve summarized the passage, and haven’t really explained it. How do you present your body to God? I would say that you give it over to him to do with whatever he wants. For example, 1 Corinthians 7:4 tells us that our wives have control over our bodies and we over theirs. Who says? God says. This means that we don’t get to do just whatever pops into our heads with our bodies. We give them to God and this means that we have given them to our wives. If your wife says, stop smoking with my body, you stop smoking. If your wife tells you to stop looking at p o r n on the internet, you stop looking at p o r n on the internet. Your body doesn’t belong to you, it belongs to God; and he’s given it to your wife to take care of.
Another way to offer your body to God is to take care to put it in situations where your mind is stimulated to love and good works. In the positive way it means to take it to Bible Studies, take it to prayer meetings, don’t neglect the gathering together of the saints (Heb 10:25). Strive to take yourself to be with the saints, talk with the saints, pray with the saints, live with the saints. On the negative side it means to avoid any and all situations where your body might get itself into sin or even temptation. If you have a problem with _______ (you fill in whatever battle you are facing), avoid the places or people who tempt you to sin in that area and take your body to be with the saints. If you have a problem being alone, never be alone. But don’t just not be alone, be with folks who will edify you and build you up in the Lord.
In addition, you have spent your whole life learning how to get along in the world. You’ve learned to stimulate your mind when you are alone, you’ve learned to get along when you get into trouble, and you’ve learned to cope when things get tough. But many of these ways of dealing with the world have come from the world and so are not any real solutions at all. You need to learn to look to Jesus, fix your eyes on Jesus, run toward the goal, batter your body, train it, run the race with endurance, to throw aside any and every encumbrance that tends to slow you down. You need to saturate your mind with the things of God and choose not to remember the things of the world any more.
Do a study on how the Bible talks about self control and how it plays out in the believers’ life. The fruit of the Spirit is self control, but exercising self control is also a command of God. It is the same with changing the heart. It is something only God can give, and yet it is a command. Repent, change your mind; Circumcise your hearts, repent, change your mind.
Above all, throughout this process pray and ask God to use the working out of your salvation to change you from the inside out into a godly, holy, righteous man, father, brother, and friend. As you give yourself to God, he will transform you into the image of his son. And this change will begin and end in a transformation of your heart and mind, soul and in many cases even your body.
So the answer to changing your heart is to constantly and consistently draw near to God in sweet fellowship, to love the saints by being with them, to love your family by playing with them, and never, never, never give the devil an opportunity to cause you to stumble. God will change your heart as you obey him (Phil. 2:12-13).