It was narrated that Jarir bin 'Abdullah Al-Bajali said:
"The Messenger of Allah never refused to see me from the time I became Muslim, and whenever he saw me he would smile at me. I complained to him that I could not sit firmly on a horse, so he struck me on the chest with his hand and said: 'O Allah, make him firm and cause him to guide others and be rightly-guided.'"
English reference: Vol. 1, Book 1, Hadith 159
Arabic reference: Book 1, Hadith 164