Via Brad DeLong, I found a year old post in which Mark Kleiman com­ments on Passover and Jew­ish law in
Avodim hayy­inu l’Pharoh b’Mitzray­im:

That, then, is the deep­er mean­ing of the first phrase in the answer to the Four Ques­tions at the Passover Seder: “Avodim hayy­inu” — “We were slaves.”

It seems, if you think about it, a rather remark­able asser­tion to put at the very cen­ter of a cel­e­bra­to­ry feast. What oth­er group, instead of boast­ing about being nobly born, makes a fuss about being descend­ed from slaves, and then per­son­al­izes it so as to say that every­one present was a slave until redeemed?

But linked to the com­mand­ments in Deuteron­o­my, that phrase comes to mean: “We were slaves” and there­fore must nev­er, nev­er, ever act like slave­own­ers. That makes sense of the empir­i­cal link between Judaism and liberalism.

Passover real­ly is an amaz­ing hol­i­day. The sym­bol­ism of the Seder is so care­ful, and the oral tra­di­tion so care­ful­ly pre­served. The Seder is a cer­e­mo­ny which reminds Jews every year that they are free peo­ple, and that their free­dom did not come easily.

We sit in the most com­fort­able chairs, eat charoset, drink, chat and have fun, because we are free, and free­dom is sweet. But there are the bit­ter herbs which we dip in salt water to remind us of the suf­fer­ings of our slav­ery and the tears our peo­ple spilled. It’s not uncom­mon for peo­ple at a Seder to read from the Dec­la­ra­tion of Inde­pen­dence, or the “I Have a Dream” speech.

It’s a cel­e­bra­tion of free­dom, a Thanks­giv­ing of sorts, but also a mourn­ing for the past. On Passover, you can­not turn some­one away from your door. You open the door, so no one need go hun­gry. You set an extra place at the table, just in case. You remem­ber those less well off.

Why is this night dif­fer­ent from all oth­er nights? If we learn the lessons of the Seder, it isn’t because we think of those less fortunate.

Here’s some­thing else to think about. There are sev­er­al sets of broth­ers in the Torah. Cain and Abel, Jacob and Esau, Isaac and Ish­mael, Moses and Aaron. All but the last fought. I was­n’t until the broth­ers found a way to serve their God togeth­er that the Jew­ish peo­ple could com­plete their covenant, becom­ing peo­ple of the law. There’s a les­son there. 

“Once we were slaves.” 

Slaves to the Pharaoh, but slaves also to hate between broth­ers. There’s a les­son there.

“Mirele” by Cha­va Alber­stein from the album For­eign Let­ters (2001, 2:38).