Halakhah zu Schemot 12:29

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.

I also found explicit with regard to the first of the holidays (Passover), which God gave to Israel prior to instructing them about the Sabbath, “on the fourteenth day of the month at evening you should eat unleavened bread, until the twenty first day of the month at evening” (Exodus 12:18), a total of “seven days” (ibid. 12:19). Thus the evening of the fifteenth is the first day. It is also written “[neither shall any of the flesh] from which you offered in the evening of the first day [be left over] until the morning” (Deuteronomy 16:4). Also, it is known that the firstborn were smitten at midnight (Exodus 12:29), yet it is written “on the day that I smote all firstborn” (Numbers 3:13, 8:17).⁴ The verse informs us that God sanctified all Jewish first born on the day that the Egyptian first born were slain. It seems likely that this took place on the first day of Passover. Also in Scripture “this day is a day of tidings…if we wait until the morning light” (2 Kings 7:9).