Maybe its commonplace, but it strikes me as odd to include in the wording of a law an assertion that the law is constitutional. It doesn't mention whether its referring to the Georgia or the U.S. Constitution, either.
Well, the legislature doesn't have the standing to define a law as constitutional, and certainly a law can't define
itself as constitutional. Laws often are written with an explanitory context (i.e. "fake Pokemon cards, being a danger to our youths, the legislature does hereby etc etc"), however, and the purpose of this language, I think, is nothing more than the legislature reminding the readers of the law of what the judiciary has already decided.
Its purpose is give permission for schools to teach a course on the Bible. Presumably without such legistlation schools cannot teach a course on any religious text.
I don't think that's true. The purpose of this bill is to allocate funding for such instruction. The law can't make something constitutional, and it can't make something legal, because all things are legal that are not made illegal by law, right? All this law seems to do is affirm the legality of teaching about the Bible, and provide some funds to do so. Now, I think you could use this law and the 14th amendment to obtain funding to teach, say, the Koran. If you're gonna fund the study of one religion's impact on Western society, there's an argument that you have to fund all of them.