Why does the fool recite this depressing verse at the wedding in "Satan in Goray"?

Question

In the beginning of the second half of Satan in Goray, at the wedding of Reb Itche Mates and Rechele, the following scene appears:

Before covering the bride's head he recited an interminable prayer. Rechele cried out only once. When Itche Mates covered her head, a rain of raisins and almonds fell on her, and all the women sobbed and blew their noses. The fool stood on tiptoe at the door so as to be seen, despite his smallness, and chanted in a melancholy way:

"The haidamaks slaughtered and martyred us.
They murdered young children, they ravished women
Chmelnicki slit open bellies, he sewed cats inside, (because of our sins!).
This is why we wail so loudly and implore
Revenge, O Lord, the blood of thy slaughtered saints!"

A woman suddenly fainted, and they poured water over her. A boy suffocating in the crowd screamed in fright. Someone stumbled over the water tun. A vessel broke.
_{Satan in Goray, part 2, chapter 1: "The Wedding" (translated by Jacob Sloan)}

Why does the fool recite this rather depressing verse at a wedding? What relevance does this plea for revenge have to the occasion?

Answer 1

While not the specific verse mentioned in the story, there was a Talmudic tradition of injecting some somberness into joyous occasions. As you can see in the below Talmudic excerpt, several examples of this occurred at weddings, including one of a somber dirge:

Rather, said R. Nahman b. Isaac: We learn it from here: Serve the Lord with fear and rejoice with trembling. What is meant by ‘rejoice with trembling’? — R. Adda b. Mattena said in the name of Rab: In the place where there is rejoicing there should also be trembling. Abaye was sitting before Rabbah, who observed that he seemed very merry. He said: It is written, And rejoice with trembling? — He replied: I am putting on tefillin. R. Jeremiah was sitting before R. Zera who saw that he seemed very merry. He said to him: It is written, In all sorrow there is profit? — He replied: I am wearing tefillin. Mar the son of Rabina made a marriage feast for his son. He saw that the Rabbis were growing very merry , so he brought a precious cup worth four hundred zuz and broke it before them, and they became serious. R. Ashi made a marriage feast for his son. He saw that the Rabbis were growing very merry, so he brought a cup of white crystal and broke it before them and they became serious. The Rabbis said to R. Hamnuna Zuti at the wedding of Mar the son of Rabina: please sing us something. He said to them: Alas for us that we are to die! They said to him: What shall we respond after you? He said to them: Where is the Torah and where is the mizwah that will shield us!

R. Johanan said in the name of R. Simeon b. Yohai: It is forbidden to a man to fill his mouth with laughter in this world, because it says, Then will our mouth be filled with laughter and our tongue with singing. When will that be? At the time when ‘they shall say among the nations, The Lord hath done great things with these’. It was related of Resh Lakish that he never again filled his mouth with laughter in this world after he heard this saying from R. Johanan his teacher.

^{(Babylonian Talmud, Berachot 31b-32a, Soncino translation, my emphasis)}