Sunan Abi Dawud, Hadith 4970

Anas said: The people of Madina were started. The Messenger of Allah (May peace be upon him) rode on the horse belonging to Abu Talhah. He said: We did not see anything, or he said: we did not see (find) any fear. I found it (could run) like a river.

حَدَّثَنَا عَمْرُو بْنُ مَرْزُوقٍ، أَخْبَرَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، قَالَ كَانَ فَزَعٌ بِالْمَدِينَةِ فَرَكِبَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَرَسًا لأَبِي طَلْحَةَ فَقَالَ ‏"‏ مَا رَأَيْنَا شَيْئًا ‏"‏ ‏.‏ أَوْ ‏"‏ مَا رَأَيْنَا مِنْ فَزَعٍ وَإِنْ وَجَدْنَاهُ لَبَحْرًا ‏"‏ ‏.‏

sunnah.com

also referenced under: Hadith 4988 (DarusSalam)