The Rama quotes the Tur who writes that those who are machmir increase in seudah on Purim Katan and ends off Orach Chaim with the verse “וטוב לב משתה תמיד” – the good of heart are always in a party-like state.
What is the significance of the Rama beginning Orach Chaim with שויתי ה לנגדי תמיד and ending Orach Chaim with וטוב לב משתה תמיד?
The Chida: the two constants for a Jew should be that Hashem is always before us and that should give us a more positive and happy outlook.
What is the nature of the obligation to have a seudah on Purim Katan vs. Shushan Purim?
Chatam Sofer: The source for celebrating Purim is a kal v’chomer: if we celebrate when we were freed from slavery – i.e. Pesach – surely we should do so when our lives were saved. If so, celebrating Purim is a דאורייתא and when it comes to a דאורייתא we say זריזין מקדימין. Thus, celebrating Purim Katan is a דאורייתא! The other aspects of Purim (Megillah, etc.) are only דרבנן.
Shiur provided courtesy of Torah Anytime