As a completion of the subject of backbiting, let us refer to slander, which means to accuse a believer falsely. It is in fact more serious than backbiting:

“One who makes a mistake or commits a sin and ascribes it to an innocent person, he only burdens himself with slander and a grave sin. (4:112)”

The Prophet (S) said: “For him who accuses falsely a male or female believer or ascribes to them false things, Allah will detain him on a hill of fire, on the Day of Resurrection, unless he provides justifiable excuse1.”

• 1. Quoted from Safinat ul-Bihar; 1/110 (as quoted from Uyounu Akhbar ir-Ridha)