Êxodo 34:18 Halacá: The Sabbath Epistle, Kol Bo & Arukh HaShulchan

Judah the Persian¹⁹ Mentioned by Ibn Ezra in his Commentary to the Pentateuch and elsewhere. Nothing is known of this scholar. (See Encyclopedia Judaica, second edition, vol. 11, p. 505.) said that the years used by Israel were solar years, because he found the festivals were on fixed dates: Passover when the barley ripens (Exodus 34:18), Pentacost at reaping time (ibid. 34:22), and Tabernacles at harvest time (Deuteronomy 16:13). However, what can be done since Moses did not specify the length of a year?²⁰ Since the Bible does not specify the exact length of a solar year, the Karites are left with the matter being undecided. This will also affect determination of the festivals. Also, how will he explain the use of the Hebrew term “hodesh” (new) for “month,” for what is renewed relative to the sun? The uncircumcised (Christians), because their years are solar years and they found that a full year contains twelve lunations, divided the days of the year into twelve parts, for this number is closest to the number of lunar months. The result is that some months are 30 days and some months are 31 days.²¹ Here Ibn Ezra accounts for the division of a year into twelve parts, even if one uses a solar calendar. However, the term “hodesh” would not be appropriate for such solar months.

On the Shabbat of the intermediate festival days, both on Passover and on Sukkot, we take out two Torah scrolls and seven go up to read from the section [that begins], Behold, you say to me (Exodus 33:12). And the reason is because it has in it, You shall observe the Feast of Unleavened Bread (Exodus 34:18). And our rabbis, may their memory be blessed, in Tractate Moed Katan, expounded that it is to include the intermediate festival days, And on the second day, the final reader [maftir] reads [about the day relating to both the first and second day of Sukkot based on] the doubt about the day. And he reads the haftara from [the section that begins], On that day, when Gog came (Ezekiel 38:18). And Rav Hai Gaon, may his memory be blessed, wrote a reason for it: Because, in the future, the war of Gog and Magog will be in Tishrei.

Shabbat is the essential point of faith in the Holy Blessed One who created the world in six days and rested on the seventh day. And anyone who does not observe Shabbat has no faith. Therefore, the Sages, throughout the Talmud compare one who violates Shabbat to one who worships idols. And all who violate Shabbat it is as if they reject the entire Torah. Therefore, immediately after the Jews left Egypt, we were commanded concerning Shabbat in Parashat Beshalach - which was before the giving of the Torah because the exodus from Egypt is testimony of God's supervision over the world to reward those who do good and the opposite to those who commit evil like the Egyptians and thoe like them. And it is evidence of God's ability to change nature like the plagues of Egypt and the splitting of the Sea and the descent of the mannah and the quail and the well. And if one does not admit that the Holy  Blessed One created the world, then he denies all these things. Therefore, he gave them all Shabbat immediately after they left Egypt. And so too our Sages said that Shabbat and the civil law were commanded at Marah which was the first stop after the splitting of the Sea, as is said in the Torah. And we see, regarding that first Shabbat, that some people desecrated Shabbat and went to collect mannah, and the Holy Blessed One said, "For how long will you refuse to keep my mitzvot and my Torah." Here it is explicit that Shabbat is a general stand in for Torah and Mitzvot. (And so too at the end of Parashat Ki Tissa it says "keep the holiday of matzot" and then after it says "six days you shall work and on the seventh day  you shall rest" for it is more common and sacred. Rather it tells us that to celebrate the holiday of matzah one needs to observe Shabbat for if there is no Shabbat there is no Pesach and no Torah).