Sahih Bukhari
Prophetic Commentary on the Quran (Tafseer of the Prophet (PBUH))
Volume: 006 / Book Number: 060 / Hadith Number: 14
Narrated Abu Said Al-Khudri:
Allah's Apostle said, "Noah will be called on the Day of Resurrection and he will say, 'Labbaik and Sa'daik, O my Lord!' Allah will say, 'Did you convey the Message?' Noah will say, 'Yes.' His nation will then be asked, 'Did he convey the Message to you?' They will say, 'No Warner came to us.' Then Allah will say (to Noah), 'Who will bear witness in your favor?' He will say, 'Muhammad and his followers. So they (i.e. Muslims) will testify that he conveyed the Message. And the Apostle (Muhammad) will be a witness over yourselves, and that is what is meant by the Statement of Allah "Thus We have made of you a just and the best nation that you may be witnesses over mankind and the Apostle (Muhammad) will be a witness over yourselves."
(2.143)