In Jeremiah 31:31-34 we read of a new covenant which the Lord shall establish and how he will write his law in the hearts of his people Israel. This prophecy in Jeremiah is fulfilled today in Christian believers who receive the Holy Spirit. We know this is so because the new covenant has been made, through the shed blood and death of Jesus Christ and the good news that believing on him and repenting we shall be saved. Jesus said in John 14:26 “But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.” And we read in Ephesians 2:12-22 that All mankind is saved through Jesus Christ and the barrier that kept the Gentiles from the promises made to Israel has been removed. “For through him we both have access by one Spirit unto the Father.” -Ephesians 2:18 (also see Galatians 3:29). “For he is not a Jew, which is one outwardly; neither is that circumcision, which is outward in the flesh: But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God.” -Romans 2:28-29 And most obviously we know that the Holy Spirit fulfills this prophecy in Jeremiah because we are told so in Hebrews 10:15-17. - “Whereof the Holy Ghost also is a witness to us: for after that he had said before, This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them; And their sins and iniquities will I remember no more. (also see Hebrews 8:8-13)
I find that this is Amazing!
"I delight to do thy will, O my God: yea, thy law is within my heart." - Psalm 40:8
"Forasmuch as ye are manifestly declared to be the epistle of Christ ministered by us, written not with ink, but with the Spirit of the living God; not in tables of stone, but in fleshy tables of the heart. And such trust have we through Christ to God-ward: Not that we are sufficient of ourselves to think any thing as of ourselves; but our sufficiency is of God; Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life." - 2 Corinthians 3:3-6