An Arabi came to the Prophet ﷺ and asked, "What is the Trumpet?"He replied, "A horn that will be blown into."
جاء أعرابي إلى النبي ﷺ فقال: ما الصور؟ قال: قرن ينفخ فيه.
Abu Dawud (4742) and Tirmidhi (2430, 3244) both narrated it through Sulayman Taymi, from Aslam Ajli, from Bishr bin Shafaf, from Abdullah bin Amr bin As, who related the hadith, and the wording given here is that of Tirmidhi. Abu Dawud's wording is, "The Sur is a horn that will be blown into." Its chain of transmission is sahih. Tirmidhi said in the first place, "Hasan, we do not know it except through the hadith of Sulayman Taymi." And in the second place, "Hasan sahih, we only know it through the hadith of Sulayman Taymi." In some manuscripts these two statements are reversed from how I have presented them. Ibn Hibban also narrated it in his Sahih (3127), as did Hakim (2/436).