הלכה אויף תהילים 42:9

And it is already known what is argued about this stringency in the book of the Zohar. Such is said in the Gemara that "midnight" is a time of will, as it is written, "And it was the half [way point] of [the] night and G-d struck the every first born..." (Shemot 12:29). And they also said that one who occupies himself with Torah at night, the divine presence is in front of him as it says, "Arise, cry out in the night, at the beginning of the watches; pour out thy heart like water before the face of the Lord" (Lamentations 2:19). Meaning, the divine presence is found with you and " beginning of the watches" is at "midnight" (if he can not get up at half way through the night, he should get up at the beginning at the beginning of the third watch (the beginning of the last third of the night)). He that is involved with Torah at night, a string of kindness is pulled on him, as it says, "By day, may the Lord command His kindness, and at night, may His resting place be with me..." (Psalms 42:9). This is called a servant of G-d as it is written, " Behold, bless the Lord, all servants of the Lord who stand in the house of the Lord at night." (Psalms 134:1). It is proper to prepare a rooster to awake him from his slumber and "midnight", which was the doing of Rabbi Akiva. He pulled along with him a rooster, even when he would go on his travels so that it would awake him at "midnight". If the rooster did not awake him, he would pay someone to awaken him.

Although it is mandatory to study by day and by night, no man acquires most of his wisdom at any but during night-time. Therefore, whosoever desires to attain the crown of the Torah should take care of all of his nights, not to spend even one of them in sleeping, eating, drinking, conversation, or in like matters, but in study of the Torah and in matters of wisdom. The sages said: "The voice of the Torah cannot be heard save at night, as it is said 'Arise and speak loud in the night'" (Midrash Raba, Song of Songs, 5.11; Erubin, 65a; Lam. 2.19. Whosoever pursues the study of the Torah by night has a thread of God's lovingkindness drawn upon himself by day, as it is said: "By day the Lord will command His lovingkindness and in the night His song shall be with a prayer unto the God of my life" (Abodah Zarah, 3b; Ps. 42.9). Any house wherein the words of the Torah are not heard by night, fire consumes it, even as it is said: "All darkness is laid up for his treasures, a fire not blown by man shall consume him" (Sanhedrin, 92; Job. 20. 26). "Because he had despised the word of the Lord, is one who hath not at all observed the words of the Torah" (Num. 15. 31; Sanhedrin, 99a). Likewise, he who has the means to pursue the Torah and does not pursue it, or he who studied and became proficient in the Torah but separated himself from it for the sake of the vanities of the world and abandoned his studies and deserted them is included among those who "had despised the word of the Lord." The sages said: "he who abandons the Torah because of wealth will end up by abandoning it because of poverty, but whosoever continues to study the Torah in poverty will in the end continue its study in wealth" (Pirke Abot, 4.11.). This subject is, moreover, defined in the Torah, for, it says: "Because thou didst not serve the Lord thy God with joyfulness and with greatness of heart by reason of the abundance of all things: therefore shalt thou serve thine enemy" (Deut. 28.47–48); and it is furthermore said: "That He might afflict thee to do thee good at thy latter end" (Deut. 8.16).¹⁴Hagigah, 9. C.

After [completing] the Maariv prayer you should set aside a time for Torah [study], to fulfill the verse: "And you shall meditate in it day and night." (Joshua 1:8) You should recognize the fact that if you eat first, you might be overcome by sleep since you are tired and nature will demand rest. This will cause you to neglect Torah study. Therefore, you should take care to set aside a time for study before your meal. However, if you are hungry and famished because you didn't eat enough by day, you may have a snack so that your mind is at ease, and then study a little. Then you may eat your meal to your satisfaction, and resume your Torah study, according to your ability. Our Sages of blessed memory said: "Night was created solely for study,"¹Eruvin 65. referring to the [long] winter nights. Nevertheless, also during the shorter nights you should study a little each night to fulfill the verse: "And you shall meditate in it day and night." From the fifteenth day of the month of Av and on²When the nights begin to get longer. V Taanis 31. you should gradually add to your study period. Reish Lakish said:³Chagigah 12. "Whoever is engrossed with Torah study at night a chord of grace is strung around him by day, as is said: 'By day God will command His grace [over us] and at night His song is with me.'⁴Tehillim 42: 9. [This can be interpreted:] "For what reason will God command His grace [over us], because His song is with me at night."⁵“His Song” being a reference to His Torah. Others stated: "Reish Lakish said: 'Whoever is engrossed in Torah study in this world which is compared to the night, God strings about him a chord of grace in the World to Come which is [compared to] day as is said: "By day God will command His grace and at night His song is with me".'" Certainly, one, who has a set time to study every day and was deterred during the day, should compensate for his commitment, at night.