Sir Godfrey Gregg
Slander, gossip, false stories, false impressions, harmful jokes all come under two commandments:
You shall not murder
You shall not bear false witness against others
Murder is all levels of intended harm.
Spreading rumors causes harm, which can result in emotional, physical, social or financial damage to a person.
Intentional lying, flesh oriented gossip, or even spreading stories due to ignorance is still false witness against a person.
People may trust who you are, and so will take your verbal statements as a true witness against someone.
The bible says that in the presence of two or three witnesses a matter is settled
One witness shall not rise up against a man for any iniquity, or for any sin, in any sin that he sins: at the mouth of two witnesses, or at the mouth of three witnesses, shall the matter be established. Deuteronomy 19:15
Therefore, when you and some others repeat the same information or testimony, you “confirm” the slander / falsehood as truth.
So, you will be as guilty as the person who originated the lie.