Except for two additional characters in the Persian (aka Farsi), Dari and Persian are the same in these translations of May Peace Prevail on Earth.
Persian / Farsi
Persian is the official language of Iran where it usually is called Farsi. The US State Department refers it as "Persian-Iranian (Farsi)." Two versions of it, known as Dari and Tajik, are among the official languages in Afghanistan and Tajikistan (although Tajik has a different alphabet). Dari is referred to by The US State Department as "Persian-Afghan (Dari)."
The name Persia means Iran, but no one calls their language Iranian. Persian is spoken there but often referred to as Farsi. If you go to Tajikistan and ask people what language they speak, they say Farsi not Tajiki. The same in Afghanistan and Tehran. Everyone refers to their own language as Farsi.
Dari and Tajik are different dialects of the Persian language. Kurdish and Sughdian are different languages, but still in the Iranian branch of Indo-Iranian languages. And while calling their own languages Farsi, native speakers discuss what to call all of them.
There are 87 Iranian languages. Persian has about 53 million native speakers, Pashto about 40 million, Kurdish about 26 million.
I have translations for Kurdish (Iraq), Pashto, and Tajiki.
I update translations as times change and the way people express things change.