Sahih BUkhari Volume 9, Book 93, Number 514:


Narrated 'Imran bin Hussain:

While I was with the Prophet , some people from Bani Tamim came to him. The Prophet said, "O Bani Tamim! Accept the good news!" They said, "You have given us the good news; now give us (something)." (After a while) some Yemenites entered, and he said to them, "O the people of Yemen! Accept the good news, as Bani Tamim have refused it. " They said, "We accept it, for we have come to you to learn the Religion. So we ask you what the beginning of this universe was." The Prophet said "There was Allah and nothing else before Him and His Throne was over the water, and He then created the Heavens and the Earth and wrote everything in the Book." Then a man came to me and said, 'O Imran! Follow your she-camel for it has run away!" So I set out seeking it, and behold, it was beyond the mirage! By Allah, I wished that it (my she-camel) had gone but that I had not left (the gathering). "