כְּאַיָּ֗ל תַּעֲרֹ֥ג עַל־אֲפִֽיקֵי־מָ֑יִם כֵּ֤ן נַפְשִׁ֨י תַעֲרֹ֖ג אֵלֶ֣יךָ אֱלֹהִֽים׃
װי אַ הינד לעכצט נאָך בעכן װאַסער, אַזױ לעכצט מײַן זעל נאָך דיר, גאָט.
Likutei Halakhot
And this is the aspect of rising at Chatzot (middle of the halachic night) which requires a person to strengthen himself very much to rise in the middle of the night to greatly mourn over the destruction of the Holy Temple. Through this is the essence of the elevation of Malchut/Kingship from the externalities and the kelipot, as explained above and as is known in the kavanot (mystical meditations). For when a person mourns the destruction of the Holy Temple, as if he himself engaged in its construction, 'for all who mourn', etc., he merits to see its future joy (Taanit 30b). Through this, a person draws down upon himself the holiness of the Holy Temple, the location of the essence of the Light of the Face which is drawn down on the Three Festivals. For at that time it was required to go up to the Holt Temple to see the Face of G-d, to receive the Light of the Face, as it is written there in the Torah as explained above. We find that the essence of the Light of the Face is in the Holy Temple and therefore one must rise at Chatzot and to greatly mourn over the destruction of the Holy Temple. Through this, one merits according to his aspect to see the its (the Temple's) future joy and to drawn down upon oneself from there the vitality from the Light of the Face which illuminates all creatures from there in the aspect of Malchut, the aspect of Lower Wisdom, in order to merit the perception of G-dliness, as explained above. And this is the remembrance of the elevation of the Festivals through the rectification of chatzot in the Psalm (Psalms 42:2) "Like a hind crying" as it is written (Psalms 42:5) "When I think of this," etc., "how I walked with the crowd, moved with them, the festive throng, to the House of G-d". This is they used go up for the Festival to the Holy Temple, as in the explanation of Rashi there. This is the aspect of three times 'face' is mentioned there, as it is written there (Psalms 42:6) "Why so downcast, my soul", etc. "I will yet praise Him for His saving face". These three times correspond to the three times during the year, which are the three Festivals where people used to go up (to the Temple) to receive the Light of the Face, as explained above. Therefore it is necessary to engage in Torah study at midnight because each and every letter of the Holy Torah are all measures and holy contractions to perceive His Blessed G-dliness. Through this, as it is written there, and by the Torah one engages in at night, one draws down a thread of holiness during the day, as our Sages of Blessed Memory stated (Chagigah 12). By this Chesed/Lovingkindness, one shortens and cuts the Malchut and builds it in wholeness at the rise of the dawn, in the aspect of (Isaiah 16:5) "And a throne shall be established in goodness", as explained above in the Torah brought above, and as is understood in the kavanot.
Likutei Halakhot
1. And this is like our Sages of Blessed Memory’s dispute regarding the knowledge, to know how to direct when midnight is, as brought down in Berachot 3, "But did David know the exact time of midnight? — Even our teacher Moses did not know it!", etc. But by David the harp was hung etc. For the main redemption in general and specifically, the redemption of the soul of each and every one depends on this knowledge and conception, to precisely direct the points of midnight. In other words, when the force of sleep strengthens upon the Jewish soul and wants to cast it down completely, G-d forbid, on account of the multitude of his sins and corruptions until he would almost almost fall completely, the Merciful One save us — then specifically Hashem Yisbarach, will shine on him in His mercy that he should remind himself of the good points that are in him and should liven himself as mentioned above, which is the aspect of rising at midnight. This is when the Shekhinah, which is the inclusion of the souls of Israel, is in ultimate smallness and minimality and then she cries in a bitter voice to Hashem Yisbarach, in the aspect of (Psalms 42:2) "Like a hind crying for water." the aspect of (Jeremiah 31:15) "A voice is heard in Ramah, lamentation, and bitter weeping" etc. And then Hashem Yisbarach, awakes His compassion and draws down a thread of mercy etc. as all this is understood in the writings. And all this is done with each Jew at all times. Since at every moment the aspect of sleep strengthens upon him, as mentioned above, until he almost almost etc. — the Merciful One save us. And then specifically must one seek his good point as mentioned above, like (Psalms 94:18-19) "When I think my foot has given way, Your faithfulness, O LORD, supports me. When I am filled with cares, Your assurance soothes my soul", as all this is like the holy teaching of 'I will sing' mentioned above. That specifically when one arrives in his mind to complete constriction, the Merciful One save us, until he wants to say, 'my foot has given way', G-d forbid, then specifically the mercies of Hashem shall hold him up according to that which is mentioned above, to awake him from his sleep and to strengthen him, which is the aspect of waking at actual midnight, which is the time of ultimate smallness. And then specifically is the aspect of waking from sleep, which is the aspect of waking from his fall through the aspect of 'I will sing unto My God while I yet have being', as mentioned above. And on this depends the redemption in general and specifically, as mentioned above. And therefore the first redemption was at midnight specifically. And so shall the last redemption be, which we hope to be soon in our days, shall be through the aspect of midnight through 'the fit and fearing ones who arise each night at midnight', that then they will awaken a great kindness, which through this they merit to draw upon themselves always the aspect of the wakening from the sleep that is at midnight, to draw upon themselves this aspect always i.e. that whenever they want to cast upon them a very great sleep and smallness. Even if they cast them down in whatever way they cast them down, G-d forbid, even if what happens to him happens. Despite this he shall always wake up specifically from amidst the force of the smallness, in the aspect of waking at midnight mentioned above. In other words, through the aspect of the yet little good that he finds in himself, and as mentioned above. And therefore Moshe did not yet know how to figure exactly when midnight was. For then it was yet before the giving of the Torah and there was not yet the awakening from below, for there were not quite yet such tzaddikim who arose at midnight and delved in Torah because it was before the giving of Torah. And therefore it was difficult to figure exactly the point of midnight, even for those who say that Moshe did know but was not quite able to speak about it and was yet afraid that perhaps they would mistake it etc. For he was not yet able to draw down this revelation openly because it was before the giving of Torah. But David did know, for the harp was hung above his bed. And the power of the harp is drawn from the Torah, as brought down in the words of the Admor Z"L. For the harp of David was five-stringed, corresponding to the five books of the Pentateuch and he would awake from his sleep until he knew how to figure the hour and the point of midnight. For David was the aspect of Mashiach who always busies with the repair of souls of Israel to awake them from their sleep through the aspect mentioned above, through the good points that he finds in each one and he teaches each one and enlightens his heart that he can seek and ask after and find in himself good points always, in order to awake him from his sleep and fall, that he should not fall completely, G-d forbid. And the main thing is to have direction at the time when he would almost almost fall, G-d forbid. Then specifically he will shine on him in His mercy and save him and awake him from the aspect of (Psalms 37:33) "Though he fall, he shall not be utterly cast down" etc., the aspect of (Id) "The wicked watches", etc.,. Hashem will not leave him in his hand". In the aspect of (Deuteronomy 32:36-39) "When He sees that their might is gone, And neither bond nor free is left. He will say: Where are their gods, The rock in whom they sought refuge, etc; See, then, that I, I am He", etc. And all this is in the power of the Torah which we have already received through Moshe Rabbeinu and through all the Tzaddikim that have been until now who thoroughly explained to us the ways of the Torah. Therefore David did know the time of midnight through the harp mentioned above for he was skillful in playing (I Samuel 16:13) "for all the holy teaching" etc., as mentioned above, is to seek the good and to enliven oneself through this. All this is the idea of the holy melodies that go out from the harp of David, as in, 'I will sing unto my God while I yet have my being', as mentioned above, the aspect of 'Awake... psaltery and harp; I will awake the dawn', as mentioned above. And through this David merited to know to figure the point of midnight mentioned above, upon which the latter redemption in general and in detail depends, for each soul of Israel. For David was Mashiach, through whom will be the final redemption, which is the complete redemption, after which there is no exile. And this is mainly through the aspect of 'songs and melodies mentioned' above, like (II Samuel 23:1) "the Mashiach of the G-d of Jacob, and the sweet singer of Israel", etc, i.e. through the aspect of 'I will sing' mentioned above. Soon in our days, Amen. And understand these things well, for it is impossible to explain it all. Just that everybody, according to whatever happens to him all the days of his life, in the days of his youth and in the days of his old age, can enliven himself always according to all these words of ours which explain a little of the truth of the holy advice and teaching of 'I will sing unto my God while I yet have my being' which the Admor Z"L very very much implored us to walk in. Happy is he who grasps onto it.