God rested on the seventh day, sanctifying and blessing it. We have no conclusive proof that He began His creative work on our Sunday so that our Saturday would be the day He rested.
God did not give any commands for people to rest on the seventh day of the week from Adam until Moses.
The first mention of the Sabbath is in Exodus 16:22-30, when God gave Israel manna to eat. They were to gather manna six days and rest on the seventh day. No manna fell on the seventh day.
The Ten Commandments required Israel to observe the seventh day of the week as the Sabbath (Exodus 20:8-11). We have not evidence that this day at that time was our Saturday.
God placed further regulations on the Sabbath. Israel was not to kindle a fire on this day (Exodus 35:3). The death penalty was imposed upon violators of the Sabbath (Exodus 31:12-18; 35:2).
The observance of the Sabbath continued from Mount Sinai until the New Testament era. Many human restrictions were attached to God’s ordinances concerning the Sabbath, such as not allowing people to go over a Sabbath day’s journey (Acts 1:12).
The Jewish religious leaders of Jesus’ day alleged that, according to their tradition, Jesus broke the Sabbath law.
There is not one mention, allusion, or suggestion in the Bible that New Testament saints should observe the event day, or any other day, as a Sabbath. We are under grace rather than the law.