What Paul preaches is not always the same as what Jesus preached. There is nothing from Jesus to suggest the Law is to be disregarded and not kept (meaning as a whole, not in the sense people are free to steal and murder).
Yeshua said it was written of old and then gave Spiritual examples of how that "work" of the Law could be followed. That is all Paul did, he saw that there were deeper meanings to the "works" of the Law that could truly save a person if they believed.
Paul repeatedly states the Law is no longer necessary. He goes so far as to say that to keep the Law will ensure God's wrathful judgment. He refers to it as being a source of sin in the world. None of the Apostles taught this or that what God stated was an abomination was now no longer.
Paul's emphasis was not on discrediting the Law, but rather the "works" or the physical keeping of the Law. Paul saw that there was a higher function of the Law and an invisible side to it that those of faith could accomplish.
God does say that circumcision is a sign of the everlasting covenant between God and Abraham and his descendants. Paul preaches that Gentiles are included in this covenant, but do not have to comply with the conditions set forth. God is specific that all males whether free or slaves or foreign will do this. Anyone that does not is cut off from his people.
Here is the problem, there was overwhelming evidence to the Jewish Believers that Elohim was taking for Himself the Gentiles, and these Gentiles were accepting and believing that Yeshua was THEIR Spiritual sacrifice, without being physically circumcised. This was the delimnia they faced in Acts 15. They knew that circumcision was commanded even before the Law, yet the evidence that Elohim was choosing Gentiles, and giving them His Spirit, without their physical circumcision, was evidence that there might be something going that they didn't fully recognize. There might be something more important than a physical "work" of the Law to be saved, something like being "cut to the heart" and having a circumcision "in Messiah" that is not made with hands. So the Gentiles were given a dispensation from doing a "work" of the Law, but had to comply with the Spiritual fulfillment of circumcision.
6And I will make thee exceeding fruitful, and I will make nations of thee, and kings shall come out of thee.
7And I will establish my covenant between me and thee and thy seed after thee in their generations for an everlasting covenant, to be a God unto thee, and to thy seed after thee.
8And I will give unto thee, and to thy seed after thee, the land wherein thou art a stranger, all the land of Canaan, for an everlasting possession; and I will be their God.
9And God said unto Abraham, Thou shalt keep my covenant therefore, thou, and thy seed after thee in their generations.
10This
is my covenant, which ye shall keep, between me and you and thy seed after thee; Every man child among you shall be circumcised.
11And ye shall circumcise the flesh of your foreskin; and it shall be a token of the covenant betwixt me and you.
12And he that is eight days old shall be circumcised among you, every man child in your generations, he that is born in the house, or bought with money of any stranger, which
is not of thy seed.
13He that is born in thy house, and he that is bought with thy money, must needs be circumcised: and my covenant shall be in your flesh for an everlasting covenant.
14And the uncircumcised man child whose flesh of his foreskin is not circumcised, that soul shall be cut off from his people; he hath broken my covenant.
He refers to the Law as a curse
No, Paul NEVER says the Law is a curse. The curse is IF you fail in continuing to DO the Law. As I have said previously, through the Sacrifice of Messiah, our failure to continue in all that is written in the Law, is nullified, because we are accomplishing the Just requirement of the Law, by our sacrifice of Yeshua (Him hanging on a tree). We are redeemed from the curse of not following what the Law says, by acknowledging Yeshua as our sacrifice, thus we are DOING what the Law said to do for our sin. Why is this so difficult to see?
10For as many as are of the works of the law are under the curse: for it is written, Cursed
is every one that continueth not in all things which are written in the book of the law to do them.
11But that no man is justified by the law in the sight of God,
it is evident: for, The just shall live by faith.
12And the law is not of faith: but, The man that doeth them shall live in them.
13Christ hath redeemed us from the curse of the law, being made a curse for us: for it is written, Cursed
is every one that hangeth on a tree:
14That the blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith. Gal 3
Here he twists scripture to fit his intent
The Law was added to increase the transgression of Adam. It was added to promote or give transgression, and by doing so, it would be easier to identify the True Seed of Abraham, because He was without transgression. Adding the Law to the Covenant to Abraham did not invalidate the promise to Abraham, it only helped to secure it.
15Brethren, I speak after the manner of men; Though
it be but a man's covenant, yet
if it be confirmed, no man disannulleth, or addeth thereto.
16Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.
17And this I say,
that the covenant, that was confirmed before of God in Christ, the law, which was four hundred and thirty years after, cannot disannul, that it should make the promise of none effect.
18For if the inheritance
be of the law,
it is no more of promise: but God gave
it to Abraham by promise.
19Wherefore then
serveth the law? It was added because of transgressions, till the seed should come to whom the promise was made;
and it was ordained by angels in the hand of a mediator.
20Now a mediator is not
a mediator of one, but God is one.
21Is the law then against the promises of God? God forbid: for if there had been a law given which could have given life, verily righteousness should have been by the law.
22But the scripture hath concluded all under sin, that the promise by faith of Jesus Christ might be given to them that believe.
23But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed.
24Wherefore the law was our schoolmaster
to bring us unto Christ, that we might be justified by faith.
25But after that faith is come, we are no longer under a schoolmaster. Gal 3
I don't want to make this a page long since there are a number of verses that convey the same meaning and I would prefer to try and stay at least close to the topic of the OP. Clearly Paul is teaching something contrary to scripture. Now that could be ok, except it would mean that God changes his mind or says things that he does not mean.
As for Abraham having faith, I honestly scratch my head with that because God tells him to go count the stars and when he does he thinks him righteous, meaning faithful to God and yet the very next words out of his mouth are to question God asking how will he know God will keep his promise. We should also keep in mind that God gave his blessing to Abraham when he went t osacrifice his son and said he did so not be cause of his faith but because of what he was going to do.