Isaiah 10:1 (King James Bible) woe unto them that decree unrighteous decrees and that write grievousness which they have prescribed
As discussed under 1 Nephi 17:25, the earliest Book of Mormon text has only the nonstandard grievious for the standard grievous, even in the Isaiah quotations (see the discussion under 2 Nephi 19:1). The critical text will maintain the nonstandard grieviousness here in 2 Nephi 20:1.