Mishneh Torah (Rambam) משנה תורה

A person is forbidden to walk behind a synagogue at the time that the congregation is praying, unless he is carrying a burden or there are two entrances to the synagogue on different sides. [In the latter instance], anyone who sees him would presume that perhaps he is planning to enter [the synagogue] through the other entrance. Similarly, if there are two synagogues in the city, a person seeing him would say that perhaps he is going to his usual synagogue. If one is wearing tefillin on his head, he is permitted to pass [a synagogue] even without any of these conditions, since the tefillin indicate that he is a person who is seriously interested in the performance of commandments, and not one to refrain from prayer.

One praying with a congregation should not lengthen his prayer excessively. [However,] he may do so when praying alone. If, after praying, he desires to [add to his prayers], he may, including even the confession of Yom Kippur. Similarly, he may add in each of the middle blessings something relevant to that blessing if he desires.

What is implied? If one has a sick person [for whom he wants to pray], he should request mercy for this person in the blessing for the sick as eloquently as he can. If he requires sustenance, he should add a supplication and request in the blessing for material prosperity. The same applies regarding each of the other blessings. Should one desire to ask for all his needs in the blessing of "the One who hears Prayer," he may do so. However, he should make no requests in the first three or last three [blessings].

A person is forbidden to taste anything or to do any work from dawn until after he has recited the Morning Prayer. He should also refrain from visiting the house of a friend to greet him before he has recited the Morning Prayer; nor should he set out on a journey before he has prayed. However, one may taste food or do work before reciting Musaf or Minchah, although he should not have a full meal close to the time for Minchah.

Once the time for Minchah Gedolah arrives, one should not enter a bathhouse, even [if only] to sweat, until he has prayed, lest he faint and neglect prayer. He should not eat, even a snack, lest he continue eating and neglect prayer, nor [should he] judge [a court case], even if only to render a final judgment, lest the decision be questioned and the matter be drawn out and cause him to miss prayer. Similarly, one should not sit in a barber's chair, even for a regular haircut, until he prays, lest the scissors break. He should not enter a tanning house close to Minchah before he has prayed, lest he see a deficiency in his work which he will deal with, and [thereby] be delayed from praying. If he begins doing one of these things, he need not stop, but may finish and then recite Minchah.

When is the beginning of a haircut? When he puts the barber's cloth over his knees. When is the beginning of a bath? When he takes off his underclothes. When is the beginning of [work in the] tanning house? When he ties the apron between his shoulders, as is the way of artisans. When is the beginning of eating? For those who live in Eretz Yisrael, it is when one washes his hands. For inhabitants of Babylonia, it is when they loosen their belts. When is the beginning of judgment? When the judges robe themselves in their taleisim and sit down. If they were [already] sitting, it is when the adversaries begin to make their claims.

Even though the Evening Prayer is not obligatory, one should not come home from his work and say: "I will eat a little and sleep a little and then I will pray," lest sleep overtake him and he sleep all night. Rather, he should [first] pray, and afterwards he may eat, drink or sleep. It is permissible to have a haircut or enter a bathhouse before the Morning Prayer. [The Sages] only established their decree before Minchah, since it is common for most people to go there during the day. However, in the morning, [these actions] are uncommon. Hence, they did not establish a decree.

A person who is involved in the study of Torah when the time for prayer arrives must stop and pray. If the study of Torah is his full-time occupation and he does not work at all, and he is involved in the study of Torah at the time of prayer, he need not stop, since the commandment of the study of Torah is greater that the commandment of prayer. Anyone involved in efforts for the welfare of the community is like one involved in Torah study.

One is forbidden to interrupt his Amidah except in a situation where his life is endangered. Even if the King of Israel greets him, he must not answer him. However, he may interrupt [to answer] a non-Jewish king, lest he kill him. A person standing in the [midst of the] Amidah who sees a non-Jewish king or tyrant approaching him should shorten [his prayer]. If unable to do so, he may stop. Similarly, if one sees snakes or scorpions approaching him in a place where their bite is fatal, he should stop [praying] and flee. If they are not fatal, he should not stop.

Women, slaves and children are obligated to pray. Anyone exempt from Kri'at Shema is also exempt from the Amidah. All those accompanying the dead [for burial], even if they are not required to carry the coffin, are exempt from the Amidah.