There are special readings from the Torah and Prophets on four Sabbaths between the one on or preceding the New Moon of (the second) Adar and the one on or preceding the New Moon of Nisan; the Torah readings deal with the Temple tax (half-SHEKEL), the commemoration of Amalek’s attack, the red heifer, and the first Passover in Egypt (685:1-6). According to some, hearing the second and third of these readings is mandatory (685:7).
Fasting before and after CHANUKAH and PURIM is permitted (686:1). The day before PURIM is the Fast of Esther; if PURIM is on Sunday, that fast is observed on the preceding Thursday (686:2). On leniencies and stringencies associated with that fast see 686:2-3.
The Book of Esther is read on PURIM both at night and during the day (687:1). On the importance of reading it see 687:2; on who must hear it see 689:1-6. In most places, it is read on the 14th of Adar (688:3,5). In some places it is read on the 15th (see 688:1-2,4); on what is done if the 15th is a Sabbath see 688:6; on what to do if it cannot be read on the proper day see 688:7-8.
Esther must be read completely and consecutively from a properly written scroll (see 690:3,5-7,14), preferably in the presence of ten people (see 690:18). On who reads it see 690:1-2,4; on reading it in other languages see 690:8-11; on reading it without proper intent see 690:12-14. For special customs associated with the reading see 690:15-17; for special features of the scroll see 691:3-4. The scroll must be written in ink on ruled parchment; many of the laws that apply to writing a Torah scroll also apply to it (see 691:1-2,5-7). Under some circumstances, a scroll that has other things written in it, or that is punctuated, is acceptable (691:8-9); on a stolen scroll see 692:11.
Before Esther is read, the blessing “…Who commanded us about reading a scroll”, “…Who performed miracles for our fathers…”, and “…Who kept us alive…” are recited, and after it is read, the blessing “…Who fights our battle…” is recited (692:1). If no acceptable scroll is available, Esther is read without reciting the blessings (691:10). The blessings may be repeated for a person who has not yet heard the reading (692:3). A person should not eat before hearing it (692:4), and should not speak while it is being read (692:2).
In the evening service, after reading Esther, VE-ATAH KADOSH is recited, preceded on Saturday night by Psalm 91 and followed by HAVDALAH (693:1). In SHEMONEH ESREH, “On the miracles…” is added to the next to last blessing in all services (693:2). HALLEL, TACHANUN, and Psalm 20 are not recited (693:3). On the Torah reading see 693:4; after it, Esther is read, followed by U-VA LE-TZION; on circumcisions see 693:4.
On PURIM, at least two gifts must be given to at least two poor people (694:1). It is customary on PURIM eve to give three coins to charity in commemoration of the half-SHEKEL; see 694:1. PURIM charity must not be used for any other purpose, and must be given to anyone who asks for it; on what to do if there are no poor see 694:2-4.
A large meal should be eaten on PURIM, primarily during the day; see 695: 1-3. It is appropriate to drink more than usual and to wear festive clothes; celebration on the 15th is also appropriate (see 695:2). On PURIM revelries see 696:8. When PURIM is on Friday, the meal should be eaten in the morning (see 695:2). “On the miracles…” is added to the second blessing of grace (695:3). Two portions of food must be sent to one or more friends; see 695:4.
It is customary not to work on PURIM, except for religious purposes; see 696:1-2. Eulogies and fasting are forbidden on both the 14th and 15th, and funeral practices are restrained (696:3), but burials are performed (see 696:7), and marriage is permitted (696:8). Mourning remains in force on CHANUKAH, but not on PURIM; see 696:4-6. Eulogies and fasting are also forbidden on the 14th and 15th of the first Adar, and TACHANUN and Psalm 20 are not recited, but these days are not otherwise celebrated; see 697:1.
Shulchan Aruch, Copyright (c) 2000 Project Genesis, Inc.