Question 1: What is the curse pronounced by the law?
This is a 'Sacred' text which means nobody explains it. If you have not shown the dedication necessary and proven your character then it is not explained, usually.
Question 2: What scripture is this written in?
This is a reference to a Jewish scripture in Deuteronomy 21 and to put it into context will take some explanation.
This law in Deuteronomy seems to me to forbid hanging people, but just reading it in English its hard to decipher that without cultural context. Maybe it doesn't forbid hanging, but even in that case I think it forbids leaving the body out. The English translation unfortunately often is taken to say "If you are hanged on a tree you are cursed." This is what I would call a 'Surface reading' that overlooks what the script is attempting to communicate. That is not what
Galatians is doing either though it may seem like it.
Galatians presumes knowledge on your part and that you already understand the Torah, but if you do not then you are stuck trying to use
Galatians to understand Torah -- which is a mistake. It doesn't teach Torah and is not designed to do so. It is a letter from Paul to the Galatians, and you must presume to know everything that the Galatians have been taught.
The law about the tree probably is saying not to leave bodies out, because it is shameful. That is probably what it means when it says they are 'Under Gods curse'. You know the term 'Namaste'? Well there is a similar principle here, in which people recognize the divinity in each other. Genesis 9:6 explains the reason not to murder is that people are made in the 'Image of God'. This may seem like difficult language, but its basically related to saying 'Namaste'. I do not kill you, because you are a moral being. Similarly I should not leave your body exposed on a tree, no matter why you have died, because it is shameful to all beings.
Galatians presumes you already understand this about the Torah, about Deuteronomy; and from there
Galatians goes into some imagery and is speaking about things in a special way that is Christian. Let me first reinforce what I have said about the body hung on a tree and that is considered shameful in Judaism to leave a body out. Actually I can only provide a hint as I see it and cannot conclude it for you, but its a good hint.
In the (long) story of David and Saul which is in
1 Kings and
2 Kings, the poor man King Saul of the tribe of Benjamin is the first king of Israel, thrust into leadership, has some success but makes some mistakes, goes crazy and kills himself. When he kills himself he also happens to be surrounded by enemy combatants, and they put his body put onto display to be pecked by the birds for days, but someone comes and takes his corpse so the birds will not peck it. I strongly suggest that this corresponds with Deuteronomy 21.
They risk their lives to take his body off of display, which is wrong if there is no compelling reason, so what is that reason? The body is dead, and they are at war. Why bother? Many people wrongly assume that it is only out of sentiment that they remove his body from view, but they would not do this I think as it risks their own lives to come out from cover where they can be overwhelmed and killed. The principle by which they do so is that it is shameful and is an offense to the divine for Saul's body to be left out to rot in public. In other words burying his body is not merely a nicety but is a duty.
This verse has always appeared as an odd argument to me on Paul's part.
It has taken some explanation to even go into that one law of Deuteronomy. To explain this letter, Galations, is also difficult. Galatians is its own creature and does not always fit with the rest of the NT very well, because it uses a lot of odd semantics. The bit where it says "Christ became a curse for us" could be explained by referring to Romans and Hebrews and some others. What Galatians is talking about is important but the words are semantically musical and beat around the bush. It is indirect speech, so it sounds like magic but is not. It is meant to sound like magic to the unlearned, but to the learned not. Perhaps there are some in the church of Galatia who grasp it and some who don't. Consider what a sacrifice does for real. It is a shared meal, and along with that shared meal comes an agreement that is called an 'Atonement' or in modern terms a 'Treaty'. The sacrifice in the Bible is a very extensive treaty which includes a complete set of laws and way of life.
Galatians is arguing that now that Christ's death functions as the basis for a complete atonement for all people if they will accept it. Discussing all of his grammar and his usages of the word 'Faith' which is extremely bizarre considering he's quoting Habakkuk where it clearly means 'Faithfulness' is all a huge jungle of words. You will not progress through it quickly though you use a machete. Here's is
Galatians arguing that now Christians can have the same close knit society that Jews enjoy, the same love, the same powerful pact through Christ and that they will not need all of the Jewish trappings and rules to accomplish it.
In the middle of all of that Galatians refers to the curse of the tree. It fits into his conversation but the explanation requires pulling from some other NT books: Hebrews and Romans and possibly some others. It has to do with how the atonement of Christ works. It has to do with the argument about the meaning of Jesus death.
