It's amazing to think of how Jesus, who was perfect, was so willing to suffer for our sakes. He not only suffered to be an example for us, but took on all the sins and sufferings of the entire world.
Some people believe it's possible to be without sin while on this earth, but the truth is, we must fight against our own sinful nature every single day.
Just as any other ritual or act of observance under the old law, I believe the act of observing the Sabbath on a particular day was replaced with the only true rest we can ever be assured of, Jesus Christ Himself.