The Four Parshios are read in the Adar closest to Nissan.
Shekalim – to remember the annual Machtzis Hashekel.
Zachor – to remember Amalek’s deed.
Parra – as a prayer to speedily become cleansed from tumah.
HaChodesh – to “sanctify’ the first month – Nissan. (ShA 1 – MB 1)
If you mistakenly read the Four Parshios and the Megilla in Adar I, they should all be repeated in Adar II. (MB 2)
When Rosh Chodesh Adar falls out on Shabbos, remove three sifray Torah:
1st one – read at least six aliyos from Parshas Hashavua.
2nd one – the last aliya before Kaddish. Read it for Rosh Chodesh.
3rd one – Maftir from Parshas Shekalim with a Haftara to match. (ShA 1)
4. When Rosh Chodesh Nissan falls out on Shabbos, likewise remove three sifray Torah. Follow the same procedure as above except read the third sefer Torah from Parshas HaChodesh with a Haftara to match. (MB 13)
In all the other scenarios of the Four Parshios, only two sifray Torah are removed.From the first, we read Parshas Hashavua. Maftir is from one of the Four Parshios with a Haftara to match. (ShA 2,3,4)
Whenever you finish reading one sefer Torah, do not do hagba until the next sefer Torah is placed down beside it. Also, do not say Kaddish after the kria of a sefer Torah before you place the next sefer Torah down next to it. (MB 6,9,12,13)
Some poskim hold that Parshas Zachor and Parshas Para are min haTorah. You should make sure to be in a place with a minyan for these Shabbosos. (ShA 7)
The baal koray and the listeners must all have intention to fulfil their obligations. This applies even according to the opinions that hold Parshas Para is only mid’rabbonon. (MB 14,15)
The Magen Avraham holds that if you must, you can fulfill Parshas Zachor by listening to the krias haTorah of Purim morning. (MB 16)
If it is impossible to attend a minyan, you should still read those parshios (from a sefer Torah) with their trop. (Rama 7 – MB 17)
There is an argument regarding the pronunciation: “zaycher Amalek” or “zecher Amalek”. It is proper to read it both ways to fulfil them both. (MB 18)
On the Arba Parshios we don’t say Kayl Molay Rachamim nor Av HaRachamim. But we do say Tzidkoscha Tzedek. (MB 18)
There is a custom to fast every Thursday during Shov’vim. The Arizal writes that these fasts are more effective to fix the sin of keri than any other fast. (BaH 2)
