Halakhah su Salmi 134:1

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.

Chapters of the Psalms, and other sections of the Torah, Prophets and Scriptures, in which all are not sufficiently fluent, must not be recited by heart. Even someone who knows [them sufficiently] to recite them by heart should be careful not to recite them by heart.¹⁶According to Mishnah Berurah you may recite Psalms by heart, since it is similar to saying prayers. However, a blind person may recite them by heart.