Humans are the most important of God's creation (1:26–31), and day 7 is the most important of the creation week. When God rested, he approved all creation. There was nothing more needed! This seven-day framework structured Israel's week.
The seventh day was the model for their weekly Sabbath. God intended for the Sabbath to celebrate his completed work. God set apart the seventh day as holy. The people dedicated it to the Creator, who also rested on this day (see Exodus 20:8–11; 31:12–17; compare Matthew 12:1–8; Romans 14:5–6; Colossians 2:16–17; Hebrews 4:1–11).