Bulugh al-Maram 1707

This Hadīth contains a severe warning to those who listen to the talk of others while they dislike that. Indeed, this is a bad manner amounting to a major sin. So, like fault, like punishment. Since a person commits this sin with his ears, he shall be punished in his ears: by the pouring of molten lead therein. This applies regardless of whether the talking people’s dislike is based on a valid reason or not.

In fact, some people dislike that others should listen to their conversations even if they say nothing shameful, wrong, or unlawful. They just do not like to be heard by anyone.