My taking a quote directly from a Yahoo site demonstrates by example that you need to substantiate your sources when you advance an argument. RealSomeone doesn't even give us that honour. S/he just throws out some quotes without proof or support and expects them to be accepted as fact.

As for where they come from in Scripture, again I have to leave that to RSO. S/he says they come from the Quran but again offers no references or proof. I can point to examples of where the Islamic Scriptures get synergy from the Jewish Scriptures but I can't be sure if they are the same ones that RSO is thinking of.

And is the Quran the last of the Holy Books? It depends on your faith perspective. Some would say that it is the last, some would say that there are others since it was written, and some would say that it isn't even holy.

For it's part, Christianity has never definitively closed off the definition of the Canon (which is partly why the Roman Catholic Canon is larger than the Bible used in other churches). Christianity also says admits that God continues to speak in new ways to His people and thus while the basic message remains unchanged, the form and interpretation of that message for a particular time must continually be made new and fresh for each audience and generation.

As for other religions having "truths", (such as Mayans, etc.), of course this is often true. At the same time, religion has historically had a powerful effect of suppressing the truth. This is true for Christianity, Judaism, Islam, Hinduism and every other religion.

For centuries, Christianity denied equality to women and black people. It threatened Copernicus with excommunication for arguing that the sun was the center of the solar system. But it eventually found ways to repent of these sins and more accurately interpret the meaning of its Scriptures. This could only happen when it stopped seeing itself as a closed system ("I think God said this so it must be true and any other point of view is therefore wrong" or as umm-salayum said, "the signs are clear to see don't need much proof for it") and instead allowed science and logic and internal debate to challenge some of these "facts" that we always thought were true.