We used to talk about the Farewell Pilgrimage without knowing that it was the farewell from the Messenger of Allah ﷺ. During the Farewell Pilgrimage, the Messenger of Allah ﷺ delivered a sermon in which he mentioned the Messiah Dajjal and spoke at length about him. Then he said, "Allah has not sent a single prophet without his having warned his people about him. Nuh warned his people about him, as did the prophets after him. Whatever may be unclear to you about him, do not let this be unclear to you, that your Lord is not one-eyed. Whatever may be unclear to you about him, do not let this be unclear to you, that your Lord is not one-eyed."
حدثني يعقوب حدثنا عاصم بن محمد عن أخيه عمر بن محمد عن محمد بن زيد يعني أبا عمر بن محمد قال
كنا نحدث بحجة الوداع ولا ندري أنه الوداع من رسول الله ﷺ فلما كان في حجة الوداع خطب رسول الله ﷺ فذكر المسيح الدجال فأطنب في ذكره ثم قال ما بعث الله من نبي إلا قد أنذره أمته لقد أنذره نوح أمته والنبيون من بعده ألا ما خفي عليكم من شأنه فلا يخفين عليكم أن ربكم ليس بأعور ألا ما خفي عليكم من شأنه فلا يخفين عليكم أن ربكم ليس بأعور
Its chain of transmission is sahih. It appears in Majma al-Zawaid 7:338, where he said, "Ahmad narrated it, and its narrators are the narrators of the Sahih," and he also said, "Part of it is in the Sahih." See also 6144, 6168.As for his saying "nuhaddithu" (we relate), it can correctly be read either as active voice or passive voice, meaning "some of us relate to others." In Majma al-Zawaid it appears as "natahaddathu," which is clear, if it was accurately transmitted from the original text and not an alteration by the printer.As for his saying "ala ma khafiya alaykum" and so on, it appears twice in this form in manuscripts H and M, and in M the mark "sahh" was placed over the second occurrence to confirm its correctness. It is mentioned only once in manuscript K and in Majma al-Zawaid.