From Sahih Muslim (Hadith 4936):
It has been reported on the authority of Umm Haram daughter of Milhan (through another chain of transmitters). She said:One day the Messenger of Allah (ﷺ) slept (at a place) near me. He woke up smiling. She said: Messenger of Allah. what made thee laugh? He said: A people from my followers were presented to me. They were sailing on the surface of this green sea... (here follows the tradition that has gone before)
Reference: Muslim 4936