Hilchos Lashon Hara, Opening – negative commands (14)

If one insulted him so much that his face changed color, one also transgresses the negative command, “Do not bear a sin through him,” where the Torah warns to not shame a Jew even when rebuking him in private, and how much more is forbidden to shame Jew when one is not rebuking him.
All this applies in private. If it happens in public, the sages already cut him off from the world to come, saying, “Whoever whitens the face of his fellow in public has no portion in the world to come.”