Hadithcore
Sahih Muslim, 1912 c
sahih

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 you 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).

وَحَدَّثَنَاهُ مُحَمَّدُ بْنُ رُمْحِ بْنِ الْمُهَاجِرِ، وَيَحْيَى بْنُ يَحْيَى، قَالاَ أَخْبَرَنَا اللَّيْثُ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنِ ابْنِ حَبَّانَ، عَنْ أَنَسِ بْنِ مَالِكٍ، عَنْ خَالَتِهِ أُمِّ حَرَامٍ بِنْتِ مِلْحَانَ، أَنَّهَا قَالَتْ نَامَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَوْمًا قَرِيبًا مِنِّي ثُمَّ اسْتَيْقَظَ يَتَبَسَّمُ - قَالَتْ - فَقُلْتُ يَا رَسُولَ اللَّهِ مَا أَضْحَكَكَ قَالَ ‏

‏ نَاسٌ مِنْ أُمَّتِي عُرِضُوا عَلَىَّ يَرْكَبُونَ ظَهْرَ هَذَا الْبَحْرِ الأَخْضَرِ ‏

‏ ‏.‏ ثُمَّ ذَكَرَ نَحْوَ حَدِيثِ حَمَّادِ بْنِ زَيْدٍ ‏.‏

References2 variants
In-Book Reference
Book 33, Hadith 231
USC-MSA web (English) reference
Book 20, Hadith 4701 (deprecated numbering scheme)