9 Then you will call, and the Lord will answer;
you will cry for help, and he will say: Here am I.
13 “If you keep your feet from breaking the Sabbath
and from doing as you please on my holy day,
if you call the Sabbath a delight
and the Lord’s holy day honorable,
and if you honor it by not going your own way
and not doing as you please or speaking idle words,
14 then you will find your joy in the Lord,
and I will cause you to ride in triumph on the heights of the land
and to feast on the inheritance of your father Jacob.”
For the mouth of the Lord has spoken.
Isaiah 58:9, 13-14 (NIV)