(כה) וַיֹּ֣אמֶר מֹשֶׁ֗ה הִנֵּ֨ה אָנֹכִ֜י יוֹצֵ֤א מֵֽעִמָּךְ֙ וְהַעְתַּרְתִּ֣י אֶל־יְהוָ֔ה וְסָ֣ר הֶעָרֹ֗ב מִפַּרְעֹ֛ה מֵעֲבָדָ֥יו וּמֵעַמּ֖וֹ מָחָ֑ר רַ֗ק אַל־יֹסֵ֤ף פַּרְעֹה֙ הָתֵ֔ל לְבִלְתִּי֙ שַׁלַּ֣ח אֶת־הָעָ֔ם לִזְבֹּ֖חַ לַֽיהוָֽה׃
(25) And Moses said, “When I leave your presence, I will plead with the LORD that the swarms of insects depart tomorrow from Pharaoh and his courtiers and his people; but let not Pharaoh again act deceitfully, not letting the people go to sacrifice to the LORD.”
(לח) וְגַם־עֵ֥רֶב רַ֖ב עָלָ֣ה אִתָּ֑ם וְצֹ֣אן וּבָקָ֔ר מִקְנֶ֖ה כָּבֵ֥ד מְאֹֽד׃
(38) Moreover, a mixed multitude went up with them, and very much livestock, both flocks and herds.
(ד) וְהָֽאסַפְסֻף֙ אֲשֶׁ֣ר בְּקִרְבּ֔וֹ הִתְאַוּ֖וּ תַּאֲוָ֑ה וַיָּשֻׁ֣בוּ וַיִּבְכּ֗וּ גַּ֚ם בְּנֵ֣י יִשְׂרָאֵ֔ל וַיֹּ֣אמְר֔וּ מִ֥י יַאֲכִלֵ֖נוּ בָּשָֽׂר׃
(4) The riffraff in their midst felt a gluttonous craving; and then the Israelites wept and said, “If only we had meat to eat!
הַכְּשֵׁרִים שֶׁבַּמִּצְרִים בָּאוּ וְעָשׂוּ פֶּסַח עִם יִשְׂרָאֵל וְעָלוּ עִמָּהֶם, שֶׁנֶּאֱמַר (שמות יב, לח): וְגַם־עֵ֥רֶב רַ֖ב עָלָ֣ה אִתָּ֑ם וְצֹ֣אן וּבָקָ֔ר מִקְנֶ֖ה כָּבֵ֥ד מְאֹֽד׃
The proper ones of Egypt came and made a Pesach sacrifice with the Jews and went out with them, as it is stated (Exodus 12:38), "And also a mixed multitude went out with them." --Exodus Rabbah 18:10
עגל מסכה. כֵּיוָן שֶׁהִשְׁלִיכוֹ לָאוּר בְּכוּר, בָּאוּ מְכַשְּׁפֵי עֵרֶב רַב שֶׁעָלוּ עִמָּהֶם מִמִּצְרַיִם וַעֲשָׂאוּהוּ בִכְשָׁפִים
Golden Calf. Once he [Aaron] threw it into the furnace, the wizards among the mixed multitude (the erev rav) that had come up from Egypt with the Israelites turned it into a calf by magic.” And further -- because Aaron declares in that moment “these are your gods” and not “our gods” -- says Rashi, “We learn that it was the mixed multitude who assembled around him and made the calf, and who afterward led Israel to go astray after it” (Rashi on Exodus 32:4).
The Israelites were joined by the airev rav (mixed multitude), the best of the Egyptians. Although God had counseled Moses against accepting them as converts, Moses insisted. He argued with God, "These people have witnessed Your great strength in Egypt. If they accompany us, they will experience additional miracles and then fully comprehend that there is no power besides You!"
Batya, the daughter of Pharaoh, was among those who joined in the exodus. She entered the Land of Israel (as did all the women of that generation, for only the men sinned in the wilderness and died there), and, moreover, was one of the nine righteous people who were taken to The Garden of Eden alive.
(י) הַרְבֵּה נִסִּים עָשָׂה הַקָּדוֹשׁ בָּרוּךְ הוּא לְיִשְׂרָאֵל, הָרַג בְּכוֹרֵי מִצְרַיִם שֶׁהָיוּ מְשׁוּלִים לִבְהֵמָה, שֶׁנֶּאֱמַר (יחזקאל כג, כ): אֲשֶׁר בְּשַׂר חֲמוֹרִים בְּשָׂרָם. הָרַג בְּכוֹרֵי שֶׁבִי, שֶׁהָיוּ אוֹמְרִים לַשָּׁבוּי שֶׁהָיָה חָבוּשׁ בְּבֵית הָאֲסוּרִין, רְצוֹנְךָ שֶׁתֵּצֵא וְיִגָּאֲלוּ יִשְׂרָאֵל, וְהוּא אוֹמֵר לֹא נֵצֵא מִכָּאן לְעוֹלָם, כְּדֵי שֶׁלֹא יֵצְאוּ יִשְׂרָאֵל, לְכָךְ דָּנָן עִמָּהֶם. מִבְּכֹר פַּרְעֹה עַד בְּכוֹר הַשְּׁבִי, מָשָׁל לְמֶלֶךְ שֶׁעָשָׂה שִׂמְחָה לִבְנוֹ וְהָרַג שׂוֹנְאָיו, אָמַר הַמֶּלֶךְ כָּל מִי שֶׁשָֹּׂמֵחַ לִי יָבֹא לְשִׂמְחַת בְּנִי, וְכָל מִי שֶׁשׂוֹנֵא לִי יֵהָרֵג עִם הַשֹּׂוֹנְאִים. כָּךְ הָאֱלֹהִים עָשָׂה שִׂמְחָה לְיִשְׂרָאֵל שֶׁגְּאָלָן, אָמַר הָאֱלֹהִים כָּל מִי שֶׁאוֹהֵב אֶת בְּנִי יָבֹא וְיִשְׂמַח עִם בְּנִי. הַכְּשֵׁרִים שֶׁבַּמִּצְרִים בָּאוּ וְעָשׂוּ פֶּסַח עִם יִשְׂרָאֵל וְעָלוּ עִמָּהֶם, שֶׁנֶּאֱמַר (שמות יב, לח): וְגַם עֵרֶב רַב עָלָה אִתָּם, וְכָל מִי שֶׁרָצוּ שֶׁלֹא יִגָאֲלוּ יִשְׂרָאֵל, מֵתוּ עִם הַבְּכוֹרִים, שֶׁנֶּאֱמַר (תהלים עח, נא): וַיַּךְ כָּל בְּכוֹר בְּמִצְרָיִם. צָעֲקוּ כֻּלָּם, שֶׁנֶּאֱמַר: וַתְּהִי צְעָקָה גְדוֹלָה בְּמִצְרָיִם, בָּאוּ כֻלָּם לַהֲרֹג פַּרְעֹה, בְּאוֹתָהּ שָׁעָה, וַתֶּחֱזַק מִצְרַיִם עַל הָעָם, וְהֵן קוֹרִין אֶת הַלֵּל, וּפַרְעֹה מַכְרִיז לְגִבּוֹרָיו בּוֹאוּ וְנִקְרָא לְמשֶׁה וּלְאַהֲרֹן. אָמַר לוֹ הָאֱלֹהִים בַּלַּיְלָה אַתָּה מוֹצִיא אֶת בָּנַי, לֹא תוֹצִיא לְבָנַי בַּלַּיְלָה, אֶלָּא יֵצְאוּ בְּרֹאשׁ גָּלוּי בַּחֲצִי הַיּוֹם, נִתְפַּזְרוּ יִשְׂרָאֵל בְּכָל מִצְרַיִם בְּאוֹתָהּ שָׁעָה, שֶׁנֶּאֱמַר: וּבְנֵי יִשְׂרָאֵל עָשׂוּ כִּדְבַר משֶׁה וַיִּשְׁאֲלוּ מִמִּצְרַיִם, וּמשֶׁה הָיָה עוֹסֵק בְּעַצְמוֹת יוֹסֵף, וּבִכְלֵי הַמִּשְׁכָּן שֶׁהֵכִין יַעֲקֹב אָבִינוּ, וְכֵן דָּוִד אָמַר (תהלים נח, יא): יִשְׂמַח צַדִּיק כִּי חָזָה נָקָם.
(10) Many miracles did the Holy One, blessed be He, do for Israel: He killed the firstborn of Egypt - that were compared to animals, as it is stated (Ezekiel 23: 20), "that their flesh is the flesh of donkeys;" He killed the firstborn of the captives; since they said to the captive that was imprisoned in the jail, "Do you want to go out and the Jews will [also] be delivered?" And he would say, "We will not ever leave from here in order that Israel not go out." That is why He judged them with [the Egyptians] - "from the firstborn of Pharaoh... to the firstborn of the captive." (Exodus 12:29) There is a parable about a king who made a joyous occasion for his son and killed his enemies. The king said, "Anyone who caused me joy should come to my son's joyous occasion, and anyone who is hated by me will be killed with the enemies." So [too], God made a joyous occasion for Israel, since He redeemed them - God said, "Anyone who loves My son should come and rejoice with My son." The proper ones of Egypt came and made a Pesach sacrifice with the Jews and went out with them, as it is stated (Exodus 12:38), "And also a mixed multitude went out with them." And all those that wanted Israel not to be redeemed died with the firstborn, as it is stated (Psalms 78:51), "And He smote all the firstborn of Egypt." They all cried out, as it is stated (Exodus 12:39), "and there was a great outcry in Egypt." They all came to kill Pharaoh. At that time, "And the Egyptians pressed upon the people (here read, as about the people)." (Exodus 12:33) And [the Jews at that time] were reciting Hallel; and Pharaoh announced to his warriors, "Come, let us call to Moshe and Aharon." God said to him, "You are releasing my children at night? You will not release my children at night, but rather they will go out [in plain sight,] in the middle of the day." The Jews dispersed into all of Egypt at that time, as it is stated (Ibid. 35), "And the children of Israel did according to the word of Moshe and borrowed from Egypt." And Moshe was busy with the bones of Yosef and the vessels of the Tabernacle that were prepared by Yakov, our father. And hence David said (Psalms 58:11), "The righteous one will rejoice, since he saw vengeance."
He said: These wealthy people are not descendants of our forefathers, but they came from the mixed multitude, as it is written: “And show you compassion, and have compassion upon you, and multiply you, as He has sworn to your fathers” (Deuteronomy 13:18), from which it is derived: Anyone who has compassion for God’s creatures, it is known that he is of the descendants of Abraham, our father, and anyone who does not have compassion for God’s creatures, it is known that he is not of the descendants of Abraham, our father. Since these wealthy Babylonians do not have compassion on people, clearly they are not descended from Abraham, Isaac, and Jacob. (BT Beitzah 32b)