Abdullah bin Buraidah (may Allah have mercy on him) says that Ubaidullah bin Ziyad had doubt about the existence of the Hawd al-Kawthar. He summoned Hazrat Abu Barzah Aslami (may Allah be pleased with him). When he came, the companions of Ubaidullah said to him that the Amir has called you so that he may ask you about the Hawd al-Kawthar. Have you heard anything from the Prophet (peace be upon him) regarding this? He replied: Yes! I heard the Prophet (peace be upon him) mention it. Now, whoever denies it, may Allah not let him drink from this Hawd.