Is keeping the sabbath a ceremonial law a moral law or a dietary law?

The Sabbath is one of the Laws of God as written by Him with His finger. The Sabbath was the first holiday ordained by God for all mankind...back in Genesis. It is moral and just, and is one of the ways we can fulfill the law as stated that we should love God with all of our being from Matthew 22:37-39. When we obey God's Law, it shows whom we serve. It does not save us...since salvation is by God's Grace.