Sunday's study is about the seventh day itself.
God began creating this world on the first day and finished creating it on the sixth day. God did His work of creation in a systematic order according to His set timetable.
Gen. 2:2 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.
The lesson study for Sunday says:
Although the noun sabbath is not mentioned in Genesis 2, the verb for "rested," from which the term sabbath is derived, proves that the Sabbath is meant (see Exod. 20:8-11). Just as six literal days came before it, the Sabbath is a literal day, as well.
Could this be why Christ said that the Sabbath was made for man, rather than the Jews only, and not man, or the Jews, for the Sabbath?