Biblical References To the Law Being Written on Man’s Heart
Jeremiah 31:33 (ESV):
33For this is the covenant that I will make with the house of Israel after those days, declares the LORD: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people.
Deuteronomy 30:14 (ESV)
14But the word is very near you. It is in your mouth and in your heart, so that you can do it.
Romans 2:12-16 (ESV)
12For all who have sinned without the law will also perish without the law, and all who have sinned under the law will be judged by the law. 13For it is not the hearers of the law who are righteous before God, but the doers of the law who will be justified. 14For when Gentiles, who do not have the law, by nature do what the law requires, they are a law to themselves, even though they do not have the law. 15They show that the work of the law is written on their hearts, while their conscience also bears witness, and their conflicting thoughts accuse or even excuse them 16on that day when, according to my gospel, God judges the secrets of men by Christ Jesus.
Hebrews 10-15-16 (ESV)
15And the Holy Spirit also bears witness to us; for after saying, 16“This is the covenant that I will make with them after those days, declares the Lord: I will put my laws on their hearts, and write them on their minds.”
James 1:21 (ESV)
21Therefore put away all filthiness and rampant wickedness and receive with meekness the implanted word, which is able to save your souls.
The Great Commandment
Matthew 22:34-40 (ESV)
34But when the Pharisees heard that he had silenced the Sadducees, they gathered together. 35And one of them, a lawyer, asked him a question to test him. 36"Teacher, which is the great commandment in the Law?" 37And he said to him, "You shall love the Lord your God with all your heart and with all your soul and with all your mind. 38This is the great and first commandment. 39And a second is like it: You shall love your neighbor as yourself. 40On these two commandments depend all the Law and the Prophets."
Jesus said the the greatest commandment in the Law is that "You shall love the Lord your God with all your heart and with all your soul and with all your mind." Since God has told us, clearly, that He has written His Law on the hearts of men in order that we shall know and do what is right, then it is clear that loving the Lord your God with all your heart, soul, and mind is right. It is also innate. God has essentially told us we are wired to believe. It is natural for man to look for God. It is natural for man to believe in God.