We learn in Bereishis 46:34

וַאֲמַרְתֶּ֗ם אַנְשֵׁ֨י מִקְנֶ֜ה הָי֤וּ עֲבָדֶ֙יךָ֙ מִנְּעוּרֵ֣ינוּ וְעַד־עַ֔תָּה גַּם־אֲנַ֖חְנוּ גַּם־אֲבֹתֵ֑ינוּ בַּעֲב֗וּר תֵּשְׁבוּ֙ בְּאֶ֣רֶץ גֹּ֔שֶׁן כִּֽי־תוֹעֲבַ֥ת מִצְרַ֖יִם כָּל־רֹ֥עֵה צֹֽאן׃

Then you shall say: Your servants have been cattle keepers from our youths until now, both we and our fathers. (Say this) so that you be settled in the land of Goshen, for the abomination of Egypt are all who graze sheep.

Rashi explains:

כִּֽי־תוֹעֲבַ֥ת מִצְרַ֖יִם כָּל־רֹ֥עֵה צֹֽאן — לְפִי שֶׁהֵם לָהֶם אֱלָהוּת:

FOR THE ABOMINATION OF EGYPT ATE ALL THOSE WHO GRAZE SHEEP — because they [sheep] are regarded by them as deities.

But as the Avudraham notes, there is a significant problem with this. First, there is no evidence that Egyptians actually worshiped sheep. Second, several pesuqim later we see that Egyptians themselves kept sheep! When the Egyptian masses run out of money with which to buy food, Yosef offers (47:16):

וַיֹּ֤אמֶר יוֹסֵף֙ הָב֣וּ מִקְנֵיכֶ֔ם וְאֶתְּנָ֥ה לָכֶ֖ם בְּמִקְנֵיכֶ֑ם אִם־אָפֵ֖ס כָּֽסֶף׃

And Yoseif said: Bring your flocks and I will give [food] to you for your flocks if the money is at an end.

The Avudraham writes that the problems the Egyptians had with shepherds was not directly about sheep, but about the zodiac, and the constellation of Aries — the ram, the zodiacal sign of the month of Nissan.

The signs of the zodiac ascend and descend at fixed types, according to the cycle of the year. The Egyptian interest in astrology reflects a mindset in which people are subject to fate. A person’s character, position in life, and future outcome are set by forces in motion when they’re born.

It struck me that this is a very useful worldview in a society as hierarchical as ancient Egypt. The people will not expect to be little more than servants of the king, and the literal slaves would never plan an uprising or to overthrow their yokes. Their low stations and miserable lives would be seen as simply what they was born to be. As long as they can keep it taboo to be shepherds, who spend the month of Nissan looking like they’re trying to overturn the natural order by lording over the sheep.

The first mitzvah we were given as a nation was to sanctify the months. Shemos 12:2:

הַחֹ֧דֶשׁ הַזֶּ֛ה לָכֶ֖ם רֹ֣אשׁ חֳדָשִׁ֑ים רִאשׁ֥וֹן הוּא֙ לָכֶ֔ם לְחָדְשֵׁ֖י הַשָּׁנָֽה׃

This new[month] shall mark for you the beginning of the new [month]s; it shall be the first of the new [months] of the year for you.

This was such an obvious starting point that Rav Yitzchaq (in a medrash found in Yalqut Shim’oni and quoted in the opening Rashi) asks why the Torah begins with creation and not this mitzvah. The word \חדש\ is used repeatedly to mean month, but the idiom chodesh actually refers to the new moon by mentioning the “new” without the “moon”. Renewal is heard three times in the verse.

From the word “לבם — for you” the gemara proves that it’s humanity’s job to sanctify the new month. We are given control of time, witnesses arrive saying they saw the new moon, and the court declares when the month begins. And as needed, they could adjust that date. The blessing in the Amidah and night-time Qiddush of a holiday is about how Hashem “מקדש ישראל והזמנים — sanctifies Israel and the times”. Hashem sanctifies the Jewish People, and we lend our sanctity to the dates we choose on the calendar.

What a difference from the Zodiacal month! Rather than man being subject to time, people are placed in control.
Then we take the sign of that very month, the lamb during Nissan, Aries, and tie it to the bedpost, eventually to slaughter it. Again, people sanctifying, rather than the sheep-force imposing our fate upon us through the stars.

וְהַ֨לֻּחֹ֔ת מַעֲשֵׂ֥ה אֱלֹהִ֖ים הֵ֑מָּה וְהַמִּכְתָּ֗ב מִכְתַּ֤ב אֱלֹהִים֙ ה֔וּא חָר֖וּת עַל־הַלֻּחֹֽת׃The tablets were God’s work, and the writing was God’s writing, engraved upon the tablets. – Shemos 32:16

The mishnah explains that Hashem chose the word חרות because it says more than just “engraved”:

אָמַר רַבִּי יְהוֹשֻׁעַ בֶּן לֵוִי: …  אַל תִּקְרָא חָרוּת אֶלָּא חֵרוּת, שֶׁאֵין לְךָ בֶן חוֹרִין אֶלָּא מִי שֶׁעוֹסֵק בְּתַלְמוּד תּוֹרָה. וְכָל מִי שֶׁעוֹסֵק בְּתַלְמוּד תּוֹרָה הֲרֵי זֶה מִתְעַלֶּה, שֶׁנֶּאֱמַר (במדבר כא) וּמִמַּתָּנָה נַחֲלִיאֵל וּמִנַּחֲלִיאֵל בָּמוֹת:Rabbi Yehoshua ben Levi said: … Do not read “graven” (charus) but rather “freedom” (cheirus), for there is no free man except one that involves himself in Torah learning; And anyone who involves himself in Torah learning is elevated, as it is said (Numbers 21:19): “and from Mattanah [a place name that means ‘gift,’ and so can refer to the gifting of the Torah], Nachaliel [literally: G-d’s heritage]; and from Nachaliel, Bamos [‘High Places’].”

Pesach teaches us that we have the freedom to be something other how we think we were made. אין מזלות לישראל — there is no astrological forces over Israel. The luchos, the Torah, spell out how to to use that freedom constructively; so that we can be more than what was written in the stars.