What do the scriptures say about keeping the Sabbath?

It is popular among Christians to say that the Sabbath has been done away with, or that we no longer need to keep the Sabbath. Some even say that the Sabbath was changed to Sunday. However, none of these claims can be supported by Scripture. There is not a single verse in the entirety of the scriptures that tells us the Sabbath was ever changed or removed, and not one verse ever tells us to stop keeping the Sabbath. Yet, there are well over one hundred verses in the scriptures that tell us to keep the Sabbath. What do the scriptures say about the Sabbath, and should we still be keeping it today?