the seventh day

The next day after the six days of creation were completed.

finished his work

Specifically, God finished the work of creation. He still performs other work.

God "rested" in the sense that he stopped working because creation was complete. God was not tired, or unable to continue.

God had a special, positive plan for the seventh day, and for every seventh day to follow.

That is, God "set apart" the day as a special day. It was not to be used in the same way as the other six days of the week.

This includes everything that God created on the earth and in the heavens, both visible and invisible things.

These references may be slightly different in some Bible translations.