Isaiah 66:23

And it shall come to pass, that from one new moon to another, and from one sabbath to another, shall all flesh come to worship before me, saith the LORD.

From one new moon to another - literally, 'as often as the new moon (shall be) in its own new moon;' i:e., in its own time every month ( ).

And from one sabbath to another - which is therefore perpetually obligatory on earth.

Shall all flesh come to worship - (; .)

Before me - at Jerusalem (Jeremiah 3:16 ).