In Hilkhoth Tefillin 4:10, the Rambam states the basic and well-known halakhah that "...shabbathoth wi-yamim tovim enan zeman tefillin..." (Translation: "Shabbat and Yom Tov are not times for ...
I have been trying to understand Isru Chag. While there is a source in tehillim for the words and the gemara derives a notion of extra celebration, there seems to be little about the scope of the day. ...
The decree of keeping two days of Yom Tov outside of Israel is because Rosh Chodesh used to be determined by Beis Din and its messengers couldn't reach all of exiles in time, thereby requiring people ...