Kurds (Shafi’is) make up the majority Sunni population of Iran (followed by Balochi Hanafis, Turkmen Hanafis and Persian Lari Shafi’is of southern Iran and Khorasani Persian Hanafis), there are over 10 million Kurds in Iran, the absolute majority are Sunnis (some are Shia, especially in Kermanshah and in Khorasan were some Kurds were deported by the Safavids and forced into Shiism)
Kurds are an Iranian rooted ethnic group, to be precise, Kurds are Median. Anthropologically, Kurds are a branch of the Iranian tree (Iranic people not to be confused with Iranian as in the sense of a modern state). Meds are one of the 3 major Aryan Tribes of Iran (Persia, Media, Parthia). Kurdish roots go back to 6th century BC, Median Kingdom of Iran. Since then, for off and on throughout the history, Kurdistan has been “a state” of Iran (or Persia if we were to use the latin term).
Kurds like other Iranian tribes such as Baloch are very closely retated to Persians. The three (Iranic) ethnic groups (Persians, Kurds and Baloch) belong to the four major ethnic people living in Iran.The other ethnic groups are Arabs and Turks. Even Kurdish language and traditions are very closely related to other Iranian traditions (like that of Persians or Lurs etc.).
Regardless of its possible roots in ancient toponymy, the ethnonym Kurd might be derived from a term kwrt- used in Middle Persian as a common noun to refer to “nomads” or “tent-dwellers”, which could be applied as an attribute to any Iranian group with such a lifestyle. The term gained the characteristic of an ethnonym following the Muslim conquest of Persia, as it was adopted into Arabic and gradually became associated with an amalgamation of Iranian and Iranicised tribes and groups in the region. Here some Islamic sources confirming that Kurds are the beduins of the Persians:
1. Imam Al-Tabari (from Tabaristan/northern Iran/Persia) said:
نعم الكرد هم بدو الفرس واحد منهم اوصى بحرق ابراهيم في النار- الطبري جلد 2 ص 58
“Yes, the Kurds are the Beduins of the the Persians, from among them is an individual who ordered Ibrahim to be burned.” (Al-Tabari, vol. 2. page 58)
2. Imam Ibn Athir had the same opinion as Imam Al-Tabari (see Ibn Athir’s tafsir
3. Ibn Qudamah famously stated that “the Kurds are the “Beduins of the Persians”. (see his Al-Muqaddimah)
4. Imam Ibn Kathir mentions the Kurds as the Beduins of the Persians and how one of them actually ordered the burning of Prophet Ibrahim (peace be upon him):
“There had never been a fire like it. They put Ibrahim, peace be upon him, into a catapult, at the suggestion of a nomadic Kurdish man from Persia.” Shu`ayb Al-Jaba’i said, “His name was Hayzan, and Allah caused the earth to swallow him up, and he will remain sinking into it until the Day of Resurrection. When they threw him he said, `Sufficient for me is Allah, and He is the best disposer of affairs.’
(Tafsir Ibn Kathir, English translation)
Similar narrations are attributed to Ibn Omar and his student Mujahid, although with weak chains (in Tafsir Al-Tabari):
يقول تعالى ذكره : قال بعض قوم إبراهيم لبعض : حرقوا إبراهيم بالنار ( وانصروا آلهتكم إن كنتم فاعلين ) يقول : إن كنتم ناصريها ، ولم تريدوا ترك عبادتها .
وقيل : إن الذي قال ذلك رجل من أكراد فارس .
و عن مـجاهد رحمه الله قال: تلوت هذه الاَية ( حَرِّقُوهُ وَانْصُرُوا آلِهَتَكُمْ ) علـى عبد الله بن عمر, فقال: أتدري يا مـجاهد من الذي أشار بتـحريق إبراهيـم بـالنار؟ قال: قلت لا. قال: رجل من “أعراب فـارس”. قلت: يا أبـا عبد الرحمن, أوَ هل للفرس أعراب؟ قال: نعم الكرد هم أعراب فـارس, فرجل منهم هو الذي أشار بتـحريق إبراهيـم بـالنار
There is also a minority view, completely shunned (rightfully) which states that Kurds are actually of Arab (!) descent. Imam Ibn Abdil-Barr Al-Maliki stated that they are actually of Arab origin who migrated to Persia and mixed with Persians and eventually became ‘Ajam (non-Arab/Persian) themselves. Ibn Abdil-Barr stated that the Kurds are descendants of Amru Muzayqa Ibn Amer Ibn Ma’ Al-Sama’. This is a rather bizarre opinion, considering that nothing in Kurdish history has EVER resembled anything Arabic. Neither linguistically, nor culturally nor ethnically (modern day DNA tests have proven that the vast majority of Kurds are of Iranic stock without a shred of doubt), except the fact that Kurds traditionally live in a nomadic way. But this is the case with all ancient people, even Persians were once nomads. This lifestyle of their might have supported the view that they are of Arab origin.