Once the people got frightened, so Messenger of Allah ﷺ rode a slow horse belonging to Abu Talha, and he set out all alone, making the horse gallop. Then the people rode, making their horses gallop after him. On his return he said, "Don't be afraid (there is nothing to be afraid of) (and I have found) this horse a very fast one." That horse was never excelled in running hence forward. (Qastalani Vol. 5)  

فَزِعَ النَّاسُ فَرَكِبَ رَسُولُ اللَّهِ ﷺ فَرَسًا لأَبِي طَلْحَةَ بَطِيئًا ثُمَّ خَرَجَ يَرْكُضُ وَحْدَهُ فَرَكِبَ النَّاسُ يَرْكُضُونَ خَلْفَهُ فَقَالَ لَمْ تُرَاعُوا إِنَّهُ لَبَحْرٌ فَمَا سُبِقَ بَعْدَ ذَلِكَ الْيَوْمِ