I have a question about the daily prayers of Judaism. I noticed on my trip to Jerusalem that a lot of those practicing Judaism got up at a certain time in the morning on the plane and faced a wall and prayed with a book in their hand. My question is why did they do this? Is there an obligation in Judaism to recite certain prayers at certain times, or do Jews pray only when they are inspired to do so?
Maimonides (Mishneh Torah, Laws of Prayer, Chapter 1) outlines the basic obligations of prayer. He writes that originally there was no fixed prayers, only an obligation to pray somewhat every day. Everyone would pray different amounts based on how 'inspired' they were.
After the destruction of the Jewish Kingdom by the Babylonians (586 BCE), the Sages of the time established fixed times for prayer with fixed content AS A MINIMUM to be recited each day. There are 5 fixed prayers:
- Shacharit: recited in the first third of the day, every day.
- Mincha: recited in the second half of the day, every day.
- Maariv (also called Arvit): recited at night every day.
- Mussaf: recited only on the Sabbath and Holidays. (after Shacharit and before Mincha)
- Ne'ila: recited only on communal fast days, particularly on Yom Kippur. (Recited after Mincha)
These prayers are viewed as obligatory. Other personal prayers to God outside of a formal structure are certainly not discouraged, and can be recited whenever and however depending on the desires of the individual.
The specific daily prayers - morning, afternoon, and evening - are not Biblically mandated. In the Talmud (Berachos 26b) there is a disagreement about what their source/basis is. One opinion is that they were originally established respectively by Abraham, Isaac, and Jacob; the other opinion is that they were established by the rabbis of the early Second Temple era and they represent the sacrifices that were offered in the Temple in the morning and afternoon, and the leftovers that were burnt at night.
Jews pray 3 times a day, facing Jerusalem. The text is mostly fixed, which is why they were holding prayer books, although certain additions can be made on an as-needed basis, such as asking for healing of a specific person. There are differences of opinion as to whether on an air plane the rules for how to pray are like the rules of someone praying on a large vessel (in which someone can easily stand and face towards Jerusalem) or whether it is like praying on a smaller vessel in which it is difficult or dangerous to stand. But I think that's a subject for another question.