Sirach 21:28 (WEB)
A whisperer defiles his own soul, and will be hated wherever he travels.
Catechism · 1
“He becomes guilty: - of rash judgment who, even tacitly, assumes as true, without sufficient foundation, the moral fault of a neighbor; - of detraction who, without objectively valid reason, discloses another's faults and failings to persons who did not know them;” — Catechism footnote: Cf. Sir 21:28.