Sorry, but you made me write a book, need to make myself clear...
Moses said cursed is the one who does not obey every word, is this not requiring perfection and anyone who breaks one command is guilt as James said?
It had nothing to do with perfection, but all to do with obedience to do that which was right in the sight of God and to refrain from sin, it was a walk to obedience. If it had to do with perfection then God knowing man could not hold them he himself would be guilty in giving laws that could not be held, men got stone for breaking the law, breaking a law that God new he could not hold.
Since when is a curse related to just loss if blessings (please rephrase), if I am correct in what you are saying, Psalm 1 tells us bless is the man that walketh, standed and sitted not and so on, meaning he is curse if he walk not in the right way.
As for Genesis 26, it is clear that Abraham has laws, commandments, charges, ordinances, statutes that he kept and I can show you passages that they new about the leviticus laws before they were given. I believe that God gave them verbally, man forgot them then he put them on tablets of stone, they forgot them or did not obey the law of God, then he stored them in the minds, writing them in the hearts and now if we walk after the Spirit the Spirit will fulfill the righteousness of the law according to the Scriptures.
God said that Abraham kept the them according to the verse, didn't he? But the laws did not make him God's righteousness, neither did it justify him, it was faith. That is what God made clear when he first spoke. I was impressed at an young age with the way you believe and believe me that I am Jewish. No one changes me, I put everything I knew aside and did not read commentary, just read and I was enlightened with the truth of God's word without letting the law to get in the way, just putting it in its right perspective. My statement of faith you read and sure you agree with me, but the law has to do with just being obedient. God says don't commit adultery, so I refrain from it, nothing to do with working, but all to do with the grace of God and the strength of his Spirit to refrain from it.
As for Galatians 3, I am telling you what it is saying.
We cannot be justify by the law because God did not give it for man to be justify, but to be obedient, if God gave it to be justified Yeshua did not have to die on the cross. The Pharisee made it what it was never intended to be which is why Yeshua told them you follow the doctrine of men.
The curse was the consequence, Yeshua took the curse of the law to the cross and his atonement redeemed us from the curse. The curse bought death and if one dies without Yeshua death (the curse of sin) will take place.
As for James 2, it is telling us to not put our trust in men who are in high places and verses 8 -13 (let's put love thy neighbors as thyself to the side for now) and let's talk about the breaking of the law... You break one you break them all because you are in violation of the Ten Commandments, remember that from this chapter the emphasis appears to be the Ten Commandment. You break one you break them all because it is sin and sin is a breaking of the law, you are in violation of the Ten Commandments.
If I understand your last question... Moses did not say that to the Gentiles and as you know some were trying to burden the Gentiles with the law, but the Apostle Paul said that it was find with the Holy Spirit to not burden them, but for them to abstain from four things, he did not say that to the Jews. In other words, some Gentiles leaned and became obedient to the law of God, nothing to do with Salvation.
I am talking about obedient to Gods law. You give your children rules and regulation to be obedient, if they disobey you correct them, if they listens they are obedient and you reward them, why, because they kept the instruction you gave them. It is all about being obedient as previously stated.
You stated, if this is true how can we claim we keep God's law. Again, I am talking about obedients, the problem is that many distort it by making it what it is not.
Now that I read James to explain explain it, it is important for you to read the story of the teacher of the law and Yeshua, him testing Yeshua because Yeshua commended him.
About perfectly, if when seek first the kingdom of God, love our God and our neighbors and walk after the Spirit the Spirit will fulfill the righteousness of the law, he is the one that does it not us. I do not have a relationship with the law, my walk is the God in Yeshua, my walk is not with the law, my walk is to work in obedience to the law of God and to grow in Yeshua, I do not live my life saying I have to keep the law of adultery, what I say is God, bring your laws to remember that if I since against you the Spirit of God convicts me of your laws to bring me to repentent. But I will say this, there are many who teach the law like in Acts 15. I wrote a book called SEEK GOD and gave it to a Messianic Rabbi, at the time he was not a Rabbi, he put my book down and told me I lean more toward Christianity which is true, why? Because my emphasis was not a relationship with the law, but with Yeshua.
Rom 8:1 There is therefore now no condemnation to those who are in Christ Jesus, true because we are redeemed from the curse of the law, we believe in Yeshua and accept the atonement, being redeem through his blood, he came to redeem those under the law (in other words, obedient to God's laws.
I hope I responded to all, a lot of writing, my eyes are weary and it is 11:00 PM, I live abroad.
It appears that you have not responded to my question and what I asked you to read.