The Messenger of Allah ﷺ was neither obscene nor vulgar in speech. He used to say, "The best among you are those with the finest character."
حدثنا أبو معاوية حدثنا الأعمش عن شقيق عن مسروق
أن رسول الله ﷺ لم يك فاحشا ولا متفحشا وكان يقول من خياركم أحاسنكم أخلاقا
Its isnad is sahih. Shaqiq is Ibn Salama al-Asadi, Abu Waail, whom we previously mentioned in 403 as one of the senior Mukhadramin among the Followers. We add here that Bukhari included his biography in al-Kabir 2/2/246-247. It is reported from Amash, who said, "Ibrahim said to me, 'Hold fast to Shaqiq, for I encountered people when they were still numerous, and they used to count him among the best of them.'" It is also reported from Asim, who said, "I heard Abu Waail say, 'I lived through seven years of the pre-Islamic era, the Jahiliyyah.'"Masruq is Ibn al-Ajda, a Follower, whose reliability we previously established in 3558. We add here that Bukhari included his biography in al-Kabir 4/2/35-36.The hadith was narrated by Bukhari 6:419, 7:80, and 10:378-379, by Muslim 2:214, and by Tirmidhi 3:138, all of them through the route of Amash, with this isnad, in similar wording. Abu Dawud Tayalisi also narrated it, 2246, from Shuba, from Amash, in similar wording. See also 6487.As for his words, "he was neither obscene nor one who indulged in obscenity," al-Hafiz said in al-Fath 6:419, meaning he did not speak obscenely, which is going beyond the proper bounds in evil speech, while "one who indulged in obscenity" refers to someone who forces himself into such speech. That is, obscenity was neither his natural character nor something he cultivated.