De Specialibus Legibus (lib. i‑iv)

Again, those who properly keep the sacred sabbath are benefited in two most important particulars, both body and soul; as to their body, by a rest from their continual and incessant labours; and as to their soul, by forming most excellent conceptions respecting God as the Creator of the universe and the careful protector of all the things and beings which and whom he has made. And he made the whole universe in one week. It is plain, therefore, from these things that the man who honours the seventh day will himself find honour. [*]( Exodus xxiii, 18.)