לא תקיפו פאת ראשכם (קדושים יט: כז)

You shall not round off the edge of your scalp.

A chassid came to The Frierdiger Rav, Maran Reb Yissocher Dov zt’’l with his peyos (sidelocks) hidden behind his ears so they shouldn’t be seen.  The Rav zt”l looked in wonder, wanting to understand why? Since before WWI, the chassid had his peyos exposed.  

The chassid excused himself, saying that due to the war, he hid his peyos so he won’t be recognized as a Yid. The Rav zt”l answered, “Actually if you had your peyos tucked out, then it would’ve protected you that no harm shall befall you.  As it says in the pasuk: “וראו כל עמי הארץ כי שם ה’ נקרא עליך ויראו ממך” – all the nations will see that Hashem’s name rests upon you – and they will fear you!”