Gentle Rebuke

Although one must speak up and rebuke his friend on occasion, it should be done in a gentle way. For this reason, the Torah warns us (Vayikroh 19:17): “You shall surely rebuke your friend and he should not carry a sin.” Rashi explains this to mean that one should not carry the sin of shaming his friend in public.

Similarly, Sefer Hachasidim (Siman 54) writes that because Aviya ben Rechavam chastised Yeravam in public in order to embarrass him, he died before his set time. Even though he was protesting for the honor of Hashem, since he did it in public and shamed Yeravam, he was deserving of punishment.