Isaiah
Isaiah 58:3BSB·traditional attribution

“Why have we fasted, and You have not seen? Why have we humbled ourselves, and You have not noticed?” “Behold, on the day of your fast, you do as you please, and you oppress all your workers.

Matthew Henry Presbyterian @wholebiblehenry

Here we have, I. The displeasure which these hypocrites conceived against God for not accepting the services which they themselves had a mighty opinion of (Isa 58:3): Wherefore have we fasted, say they, and thou seest not? Thus they went in the way of Cain, who was angry at God, and resented it as a gross affront that his offering was not accepted.

Commenting on Isaiah 58:3-7

John Gill Reformed Baptist @doctorgill

Wherefore have we fasted, say they, and thou seest not?.... Our fasting; takest no notice of it; expresses no approbation of it, and pleasure in it: this is put for all religious services, being what was frequently performed under the Old Testament, not only at certain times appointed by the Lord, but on other occasions, and of their own fixing; in which they put their...

Jamieson-Fausset-Brown Reformed @jfbcommentary

Wherefore--the words of the Jews: "Why is it that, when we fast, Thou dost not notice it" (by delivering us)? They think to lay God under obligation to their fasting (Psa 73:13; Mal 3:14). afflicted . . . soul-- (Lev 16:29). Behold--God's reply. pleasure--in antithesis to their boast of having "afflicted their soul"; it was only in outward show they really enjoyed themselves.