Sahih Bukhari Volume 4, Book 54, Hadith Number 414.
Narated By Imran bin Husain : I went to the Prophet and tied my she-camel at the gate. The people of Bani Tamim came to the Prophet who said “O Bani Tamim! Accept the good tidings.” They said twice, ‘You have given us the good tidings, now give us something” Then some Yemenites came to him and he said, “Accept the good tidings, O people of Yemem, for Bani Tamim refused them.” They said, “We accept it, O Allah’s Apostle! We have come to ask you about this matter (i.e. the start of creations).” He said, “First of all, there was nothing but Allah, and (then He created His Throne). His throne was over the water, and He wrote everything in the Book (in the Heaven) and created the Heavens and the Earth.” Then a man shouted, “O Ibn Husain! Your she-camel has gone away!” So, I went away and could not see the she-camel because of the mirage. By Allah, I wished I had left that she-camel (but not that gathering).
Narrated ‘Umar: One day the Prophet stood up amongst us for a long period and informed us about the beginning of creation (and talked about everything in detail) till he mentioned how the people of Paradise will enter their places and the people of Hell will enter their places. Some remembered what he had said, and some forgot it.