An interpretation of Isaiah 58: 13-14 (note: King James translation)
13 If thou turn away thy foot from the sabbath, from doing thy pleasure on my holy day; and call the sabbath a delight, the holy of the Lord, honourable; and shalt honour him, not doing thine own ways, nor finding thine own pleasure, nor speaking thine own words:
14 Then shalt thou delight thyself in the Lord; and I will cause thee to ride upon the high places of the earth, and feed thee with the heritage of Jacob thy father: for the mouth of the Lord hath spoken it.
The school of Rabbi Jannai interprets:
'and thou shalt honour it', (note that KJV translates “honour him” – vs honoring the Sabbath) that thy Sabbath garments should not be like thy weekday garments, and even as R. Johanan called his garments 'My honourers'. (i.e. the clothes make the man).
'Not doing thine own ways', that thy walking on the Sabbath shall not be like thy walking on weekdays.
'Nor finding thine own affairs': (note KJV translates as “pleasure”) thine affairs are forbidden, the affairs of Heaven [religious matters] are permitted.
'Nor speaking thine own words:' that thy speech [conversation] on the Sabbath should not be like thy speech on weekdays. (i.e. business talk) 'Speaking': speech is forbidden, but thought [about mundane matters] is permitted.