And I will turn your feasts into mourning, and all your songs into lamentation; and I will bring up sackcloth upon all loins, and baldness upon every head; and I will make it as the mourning of an only son, and the end thereof as a bitter day. I will turn your feasts into mourning - See on Amos 8:3 (note).
A bitter day - A time of grievous calamity.