Which is more severely punished by Allah: injustice or backbiting?

Injustice and backbiting are two great sins, and some types of injustice are more severely punishable than backbiting, especially if the injustice is polytheism, which condemns its perpetrator to Hellfire, as confirmed by His Almighty's saying: "Indeed, polytheism is a great injustice." The punishment for the backbiter is also severe, as mentioned in the Hadith of the Mi'raj about people who had copper claws with which they scratched their faces and chests, and they were "those who consumed people's flesh and assailed their honor." Both are among the most severe punishments for perpetrators of major sins if they do not repent with sincere repentance. However, the greatest injustice is unforgivable by Allah, and its punishment is more severe than the punishment for any other sin.