"Adam was to gather with his descendants on the Sabbath, at the tree of life." He was "to preach, i.e., to proclaim God and His praises and the glory of creation….and to exhort them to a holy and sinless life and to a faithful tilling and keeping of the garden….
"God also ordained that we should work for six days, and celebrate the seventh…. Therefore, when man would have worked for six days in the week, he would on the seventh have ceased working – both he and the animals – especially so that he could then have had time to hear the Word of God." Note here the triune elements of all worship: praise, prayer, and the Word of God!