Should the fast that I choose become like this, as a day for earthling man to afflict his soul? For bowing down his head just like a rush, and that he should spread out mere sackcloth and ashes as his couch? Is it this that you call a fast and a day acceptable to Jehovah?”​—Isaiah 58:3-5.

In an attempt to whitewash their behavior, they engage in showy displays of mourning​—drooping their heads like bulrushes and sitting in sackcloth and ashes—​in apparent repentance for their sins. Of what value is all of this if they continue to rebel? They show none of the godly sorrow and repentance that should be associated with sincere fasts.