Abu Umama Taymi reported,
I said to Ibn Umar, "We work as transporters for hire during Hajj, so do we have any Hajj?"He replied, "Do you not perform Tawaf around the Kabah, come to Arafat, stone the pillars, and shave your heads?"We said, "Yes, we do."Ibn Umar then said, "A man came to the Prophet ﷺ and asked him the same question you have asked me, and he did not answer him until Jibreel 
descended upon him with this verse, 'There is no blame upon you for seeking bounty from your Lord' [Baqarah 2:198]. So the Prophet ﷺ called him over and said, 'You are pilgrims.'"
Ahmad 6434
Sahihحدثنا أسباط حدثنا الحسن بن عمرو الفقيمي
عن أبي أمامة التيمي قال
قلت لابن عمر إنا نكري فهل لنا من حج قال أليس تطوفون بالبيت وتأتون المعرف وترمون الجمار وتحلقون رءوسكم قال قلنا بلى فقال ابن عمر جاء رجل إلى النبي ﷺ فسأله عن الذي سألتني فلم يجبه حتى نزل عليه جبريل عليه السلام بهذه الآية {ليس عليكم جناح أن تبتغوا فضلا من ربكم} فدعاه النبي ﷺ فقال أنتم حجاج
Its chain of transmission is sahih. Abu Umama al-Taymi is trustworthy. Ibn Main deemed him trustworthy and said, "His name is not known," as mentioned in Tahdhib 12:14. Bukhari gave his biography in Kuna (7), saying, "Abu Umama." Shuba said, "Abu Umayma al-Taymi, who heard from Ibn Umar. Ala and Shuba narrated from him." It is said that his name was Amr bin Asad.Dulabi also mentioned him in Kuna (1:116), saying, "I heard Abbas say, I heard Yahya (meaning Ibn Main) say, Shuba narrated from Abu Umayma al-Arabi." Ala bin Musayab also narrated from him and said, "Abu Umama al-Taymi," while Shuba said, "Abu Umayma." The narration of Ala bin Musayab from him will come right after this one. However, here, in the version found in the Musnad at 6435, his name is left unspecified, saying only, "from a man of Banu Taym Allah." But he was named by his kunya, Abu Umama, in reports found outside the Musnad, as we will mention. He is the Taymi, from Banu Taym Allah, though in many references he appears as Tamimi, as in Tahdhib 8:192, which is a scribal or printing error.This hadith was also related by Tabari in his tafsir, 2:164, from Taliq bin Muhammad al-Wasiti, from Asbat, who is Ahmad's teacher here, with this same chain of transmission. Ibn Kathir quoted it in his tafsir, 1:163, from the Musnad at this point, and also quoted it again, 1:264, from the tafsir of Tabari. We will mention the rest of its sourcing in the chain that follows.His saying, "nukri," with the nun vocalized with damma, is the present-tense form of the quadriliteral verb. One says, "akra dabbatahu" (he hired out his mount), so he is called "mukri" and "kari," on the patterns of mufil and faeel, from kira, meaning the fee paid by the one who hires.His saying, "and you come to Muarraf," with the doubled ra vocalized with fatha, means standing at Arafah. It says in Lisan al-Arab, "The people performed the arafah, meaning they stood at Arafah... and this is Muarraf, referring to the standing place at Arafat." Yaqut said, "Muarraf is the passive participle from irfan, the opposite of ignorance, and it is the place of standing at Arafah."