I heard someone mention a posuk that says "Don't be ashamed of people who may laugh at us." Where does this posuk come from?
I suspect this is a rabbinic aphorism commonly formulated as:
"אל יבוש מן המלעיגים"
"Al yevosh min hamal'igim." Don't be embarrassed of those making fun of you for doing the right thing.
I don't have a Bar-Ilan DVD handy so I can't comprehensively source it. But here's Rabbi Google:
Metzudat David's commentary to Psalms 25:3 :
אז גם כל המקוים לך לא יבושו מן המלעיגים כי יראו כי יש תקוה
All those who believe in You won't be ashamed of those making fun ...
Shulchan Aruch 1:1 formulates similarly:
Velo yitbayesh mibei adam hamal'igim alav bavodat Hashem yitbarach.
(Though the commentaries note -- just because you shouldn't be embarrassed of mitzva observance, doesn't mean you should start up with haters for the sake of getting into fights!)
The simplified formulation -- "al yevosh min hamal'igim" -- appears in a sermon of the Apta Rav just over a hundred years ago, as "that quote said in many places."
There's also a Rabbi Rakeffet mp3 where he plays a recorded interview of Rabbi Dovid Cohen of the Gvul Yavetz shul in Brooklyn. Years earlier, Rabbi Joseph Dov Soloveichik had delivered a eulogy for his uncle, the Brisker Rav [Yitzchak Zev Soloveitchik], in which he said that the Brisker Rav was completely uninvolved with politics. Other Charedi leaders like the Chazon Ish would meet with David Ben-Gurion, but not the Brisker Rav. Rabbi Cohen, a young student at the time, became incensed with what he perceived as an insult to the Chazon Ish, and found himself shouting back at Rabbi Soloveichik. Rabbi Cohen reports that shortly thereafter he received a message (phone call, I think?) from his mentor, Rabbi Yitzchak Hutner, saying? "Al yevosh min hamal'igim." I.e. you did the right thing, hold your head up high.