What is "bitter cup"?
I don't understand the last two sentences of the following paragraph. What does it mean by "That bitter cup has come out of its cupboard"?
When the plague came to London in 1665, Londoners lost their wits. They consulted astrologers, quacks, the Bible. They searched their bodies for signs, tokens of the disease: lumps, blisters, black spots. They begged for prophecies; they paid for predictions; they prayed; they yowled. They closed their eyes; they covered their ears. They wept in the street. They read alarming almanacs: “Certain it is, books frighted them terribly.”The government, keen to contain the panic, attempted“to suppress the Printing of such Books as terrify’d the People,”according to Daniel Defoe, in “A Journal of the Plague Year” , a history that he wrote in tandem with an advice manual called “Due Preparations for the Plague” , in 1722, a year when people feared that the disease might leap across the English Channel again, after having journeyed from the Middle East to Marseille and points north on a merchant ship.【 Defoe hoped that his books would be useful “both to us and to posterity, though we should be spared from that portion of this bitter cup.”That bitter cup has come out of its cupboard.】