Saturday is defined as the 7th day of the week. The 7th day according to the word of the Lord is the sabbath day, the day of rest. Many of us recognize Sunday as the sabbath day as this is the day we go and worship the Lord.
Genesis 2:1-3 (KJV)
1 Thus the heavens and the earth were finished, and all the host of them.
2 And on the seventh day God ended his work which he had made; and he rested on the seventh day from all his work which he had made.
3 And God blessed the seventh day, and sanctified it: because that in it he had rested from all his work which God created and made.
Exodus 20:8 (KJV)
Remember the sabbath day and keep it holy.
Whether you celebrate the sabbath day on Saturday or Sunday, remember to rest and give honor to God.