[22].Surah Al-Hajj [The Pilgrimage]: Ayat 19-22

Ayat 19. These two opponents (believers and disbelievers) dispute with each other about their Lord; then as for those who disbelieve, garments of fire will be cut out for them, boiling water will be poured down over their heads.

Ayat 20. With it will melt or vanish away what is within their bellies, as well as (their) skins.

Ayat 21. And for them are hooked rods of iron (to punish them).

Ayat 22. Every time they seek to get away there from, from anguish, they will be driven back therein, and (it will be) said to them: "Taste the torment of burning!"

[Tafseer] These two antagonists dispute with each other about their Lord: But those who deny (their Lord),- for them will be cut out a garment of Fire: over their heads will be poured out boiling water. Two antagonists: i.e., parties of antagonists, viz., Men of Faith, who confess their Lord and seek to carry out His Will, and Men who deny their Lord and defy His Will. With it will be scalded what is within their bodies, as well as (their) skins. The punishment, expressed in physical terms, will be all-pervading, not merely superficial. In addition there will be maces of iron (to punish) them. Read this with the next verse. There will be no escape from the final Punishment judged after the time of repentance is past. Every time they wish to get away there from, from anguish, they will be forced back therein, and (it will be said), "Taste ye the Penalty of Burning!" 

Hazrat Anas (May Allah be pleased with him) said: The Messenger of Allah [SAWW](PBUH) said, "During the Miraj (the Night of Ascension), I saw a group of people who were scratching their chests and faces with their copper nails. I asked, `Who are these people, O Jibril?' Jibril replied: `These are the people who ate flesh of others (by backbiting) and trampled people's honour.''

[Abu Dawud Hadith # 4878].

Lesson : as mentioned above in Surah Al-Hajj Ayat 21."And for them are hooked rods of iron (to punish them)" "These are the people who ate flesh of others'' is a metaphor for backbiting. "To trample people's honour'' is akin to harming their goodwill and honour. The punishment for these things mentioned in Hadith makes their seriousness obvious.