Isaiah 58:4-5

4The facts are that you fast only for strife and brawling and to strike with the fist of wickedness. You do not fast as you do today to make your voice heard on high.

5Is a fast such as this what I have chosen, a day for a man to humble himself [with sorrow in his soul]? Is it only to bow down his head like a reed And to make sackcloth and ashes as a bed [pretending to have a repentant heart]? Do you call this a fast and a day pleasing to the Lord?