What are the consequences of insulting and cursing entire peoples in this life and the hereafter?

Generalized cursing of the people of a country or a nation is a grave sin and a blatant lie. It is considered the greatest slander against those who are innocent. Repentance for this sin is obligatory between the individual and their Lord. It is not necessary to seek forgiveness from all of them, as that is impossible. It is not considered backbiting to malign an entire country or unspecified people. Rather, backbiting is specifically directed at identifiable individuals, mentioning about them what they dislike. In such a case, one is not subject to punishment for the right of each individual, but rather for the right of Allah, once. It is commendable to seek forgiveness for the people of the country and to praise them, as this is more likely to clear one's conscience and increase the hope of accepted repentance.