Isaiah 66 — It’s basically the dumb dog watchmen killing themselves because their feasts are polluted/profane. They also have blood on their hands. Therefore, when they do the feasts, it is reproachful to the servants.

Zephaniah 3:17-18

17 The Lord thy God in the midst of thee is mighty; he will save, he will rejoice over thee with joy; he will rest in his love, he will joy over thee with singing.

18 I will gather them that are sorrowful for the solemn assembly, who are of thee, to whom the reproach of it was a burden.

God will sing a song for those that were sorrowful here.

Zephaniah 3:18 (CJB) “I will gather those of yours who grieve over the appointed feasts and bear the burden of reproach [because they cannot keep them].