Deuteronomy 24:8–9, Remember what YHVH … did unto Miriam. Moses’ sister Miriam was struck with a skin disease because she spoke evil against her brother. Slander is defined as making false or damaging statements about someone. The Torah keeps returning to the subject of “gossip, slander and other forms of selfish and antisocial behavior” (The ArtScroll Stone Edition Chumash, p. 1060).
Obviously such activity was a problem then as it continues to be now. It can literally destroy human relationships, families, marriages, ministries and congregations.
The interesting things is that those committing such sins usually fail to admit they are doing it, yet such is all too clear to those who are their victims. (Read Prov 6:16, 19 and Jas 3:1–12.)