"You shall not oppress a stranger, for you know the feelings of the stranger, having yourselves been strangers in the Land of Egypt" (Exodus 23:9). This commandment - the negative mitzvah not to oppress the stranger, combined with the positive mitzvah to love the stranger - is repeated more times than any other in the Torah. And, again and again, the justification is clear - you were strangers in the lang of Egypt.

From the ADL Hagaddah:

Our ancestors were immigrants to Egypt. They came fleeing economic insecurity (famine in Canaan; see Gen. 42:5) and in search of stability and freedom. At first, because Pharaoh knew Joseph personally, he welcomed his family. But then, a lack of familiarity led to contempt; “a new king arose over Egypt who knew not Joseph.” (Ex. 1:8)

Despite the contributions of the Israelites to Egyptian society, the new Pharaoh’s ignorance led to fear and he began to agitate and legislate against them: “Look, the Israelite people are much too numerous for us. Let us deal shrewdly with them, so that they may not increase; otherwise
in the event of war they may join our enemies in fighting against us and rise from the ground.”
(Ex. 1:9–10) The resulting experience of oppression became the point of reference for one of the most profound expressions of Jewish ethics (Ex. 23:9).

Nor was the Exodus the last time when Jews have been immigrants and refugees, when we have ourselves been the oppressed stranger. We carry with us a history of exiles and pogroms, of being turned away at borders - a history which continues today for many Jews around the world.

We remember this religious tradition and shared experience when we see the 11 million undocumented people in the United States today, who face the constant threat of deportation, separated families, and uncertain futures. So too when we see undocumented African migrants in Israel, who the right-wing government has demonized as "infiltrators" and a "demographic threat." Xenophobic political leaders in both countries have denied the stranger freedom and dignity, then briefly offered compromise, then reneged on their promises. We have been here before.

We dedicate our fourth cup to justice for immigrants and refugees - both to the negative mitvah of refusing to be complicit in oppressing the stranger, and to the positive mitzvah of loving the stranger by taking action for a better world. With these commitments in mind, we bless the fourth cup. (We raise our cups.)

בָּרוּךְ אַתָּה יְיָ אֱלֹהֵינוּ מֶלֶךְ הָעוֹלָם
בּוֹרֵא פְּרִי הַגָּפֶן

Baruch atah, Adonai Eloheinu, Melech Haolam, 
borei p'ri hagafen.

(We drink.)

haggadah Section: Tzafun