Muslims, not Arabs. Also you are mistaken about Arabs passing Persian knowledge. Initially invading Arabs were given to destroying books. It was Muslim Persians who did most of the translation, and subsequently elaboration of the ancient world’s thinking into the Muslim civilization and from there to Europe. And yes, they wrote in Arabic just like Isaac Newton wrote Principia in Latin. And most of us now write in English, but are we Anglos?

p.s. important to amend this here to note that certainly, Muslim civilization had many towering Arab (and non-Persian non-Arab) intellects as well. In my personal opinion, the correct terminology would be Muslim and Islamic (since it certainly was that) instead of Arab or Arabic. The latter apparently is favored by European “Orientalists” but it is both incorrect and further it is divisive.