It is the ministration of the law that has changed. It went from Tables of stone and parchment (the Book of the Law) to the fleshly tables of the heart. Thus saith the Word in Romans 9:30-33
What shall we say then? That the Gentiles, which followed not after righteousness, have attained to righteousness, even the righteousness which is of faith. But Israel, which followed after the law of righteousness, hath not attained to the law of righteousness.Wherefore? Because they sought it not by faith, but as it were by the works of the law. For they stumbled at that stumblingstone;As it is written, Behold, I lay in Sion a stumblingstone and rock of offence: and whosoever believeth on him shall not be ashamed.
As seen above Faith is the issue. Faith is the stumbling stone in which Israel stumble on.
Let's continue. Romans 10:6-8,4
For Christ is the end of the law for righteousness to every one that believeth. For Moses describeth the righteousness which is of the law, That the man which doeth those things shall live by them. But the righteousness which is of faith speaketh on this wise, Say not in thine heart, Who shall ascend into heaven? (that is, to bring Christ (THE WORD) down from above
Or, Who shall descend into the deep? (that is, to bring up Christ (THE WORD) again from the dead.) But what saith it? The word (CHRIST)is nigh thee, even in thy mouth, and in thy heart: that is, the word of faith, which we preach;
(Rom 10:4-8 KJV)
For Christ (the Word in the heart and mouth; which is the faith in which we speak) is the end of the law (on tables of Stone and and on parchment) for righteousness to every one that believeth.
Do we then make void the Law through Faith? Nay we establish it!
For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people:
(Heb 8:10 KJV)
GOD'S Laws, HIS Word, Christ in the heart, mind and mouth. A New Ministration! A new Manifestly declared to be the Epistle of Christ!
In that he saith, A new he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.
(Heb 8:13 KJV)
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;
(2Co 3:3-5 KJV)