Chasidut for Berakhot 69:32

This corresponds to the 4 cups of wine at the Passover Seder. Wine has two parts, as our Rabbis Z"L said, "if a person is worthy it makes him a head and if he is not worthy it makes him a poor person". Yoma 76b. This means that a person's knowledge is elevated by the wine, and being that the essence of knowledge is the revelation of providence, knowledge of providence is enhanced by drinking wine and one becomes a 'head'. But when a person is not worthy, the opposite happens and one becomes poor, for the true pauper is he who lacks knowledge, which is the main cause of material poverty. When a person lacks knowledge of providence, which is the essence of knowledge, this causes poverty, as in, "you shall eat it with despair" (Genesis 3:17), representing oppression and poverty that come on account of the blemish of eating of the tree of knowledge of good and evil, which corresponds to natural sciences. Furthermore, nature corresponds to darkness and night, corresponding to the blemish of the moon, which is the root source of poverty, as is known. Wine is therefore comprised of both elements: it brings on sleep, which corresponds to nature, which corresponds to night and sleep, and when one is worthy, it arouses from sleep, as in, "your pallet is like good wine which makes the lips of the sleeping speak". Song of songs 7:10. Good wine, which comes from the realm of holiness, arouses a person from sleep, represented by speech. During sleep, speech disappears, while good wine arouses from sleep and evokes speech, which comes from knowledge, as in 'makes the lips of the sleeping speak', which corresponds to providence, corresponding to the arousal from sleep. And since wine is comprised of both elements, when a person is worthy it represents knowledge, Providence, as in, "wine that makes glad", corresponding to the world of the future, as in "wine makes glad" (Psalms 104:15). And when one is not worthy it is an intoxicating wine, which confuses knowledge and errs with natural sciences, which corresponds to sleep. Therefore wine must be carefully guarded from the touch of a non-Jew, more than anything else. Nothing else in the world besides wine becomes forbidden by the touch of a non-Jew. As soon as a non-Jew touches wine, and touch is with the hands, the wine is drawn into the realm of nature, which corresponds to the non-Jew, since the wine itself is comprised of both aspects. Therefore a non-Jew, who corresponds to nature, makes the wine impure with the touch of his hand, for the wine is immediately drawn into the realm of nature, and is therefore unsuitable for a Jew, who is above nature, and whose food and drink should be holy, since the knowledge of providence is drawn through food and drink. Therefore, the blemish of the wine is specifically by their touch with the hands, for the blemish of the knowledge of providence is mainly through a blemish of the hands, of the 28 phalanges of the hands, which correspond to the 28 letters of creation. The hands of the non-Jews though, are the opposite of this, and are in the category of "the hands are the hands of Esau" (Genesis 27:22), corresponding to the mistaken belief in nature, corresponding to "my power and the might of my hand", and therefore wine is blemished by the hand of a non-Jew. This forbidden wine is then in the category of the mistaken belief in natural sciences, which corresponds to sleep. This is alluded to in the word Nesekh, נֶסֶךְ, the term for forbidden wine, as in, "For G-d Nasakh נָסַךְ (poured) a spirit of slumber" (Isaiah 29:10), which refers to stargazers who have a mistaken belief in the constellations. Therefore at the time of the Exodus from Egypt, when Providence was revealed, it is a commandment to drink 4 cups of wine, for wine is then in the category of 'if one is worthy the one becomes a head', for now at the Passover Seder, knowledge is elevated and providence is greatly revealed through the wine, for G-d drew Providence and broke the night, the sleep, as in "around midnight I will go out within Egypt". Wine is then in the category of 'wine makes glad' and a person is able to speak and tell the story of the Exodus from Egypt on this night, by means of the wine as in 'wine makes the lips of the sleeping speak'. This corresponds to "song is only recited on wine". Berachot 35b. For all songs are drawn from the world of the future, when song will be aroused in the world, as stated in the holy Zohar III 286b, as in, "Then Moses will sing". Exodus 15:1. It does not say 'sang', in the past tense, but 'will sing' in the future, teaching us that he will sing in the world of the future. Sanhedrin 91b. This is because the essence of song comes from the world of the future, when Moses will sing, for song will then be aroused in the world. This is the source of all songs - song in this world over miracles, for all miracles come about by G-d drawing providence from the end of the world, from the world of the future, into this world. And when a miracle takes place, we draw song from the world of the future into this world, which is all the songs for the miracles that we sing. Therefore, song is only recited over wine, for wine will then be absorbed into holiness, corresponding to knowledge of providence, for the essence of song is drawing providence, which is the song for the miracle, into this world, which is why song should be over wine. This is represented by the 4 cups of wine at the Passover Seder, corresponding to the Four Kingdoms. When wine is absorbed into holiness, corresponding to Providence, all exiles of the Four Kingdoms are subdued, for their main power is through nature, and by means of the Providence that is revealed by the knowledge that is drawn by the 4 cups of wine, they are all eliminated.