Sahih Muslim 166aBook 1, Hadith 325
Which valley is this? They said: This is the valley of Azraq, and he observed: (I perceive) as if I am seeing Moses (peace be upon him) coming down from the mountain track, and he is calling upon Allah loudly (saying: Here I am! at your service! ). Then he came to the mountain track of Harsha. He (the Holy Prophet) said: Which is this mountain track? They said: It is the mountain track of Harsha. He observed (I feel) as If I am seeing Yunus (Jonah-peace be upon him) son of Matta on a well- built red dromedary, with a cloak of wool around him and the rein of his dromedary is made of the fibres of date-palm, and he is calling upon Allah (saying: Here I am! at your service, my Lord! ). Ibn Hanbal said in the hadith narrated by him: Hushaim said that the meaning of khulba was fibre of date-palm.