From Sahih Muslim (Hadith 6364):
Jarir reported:Since I embraced Islam Allah's Messenger (ﷺ) never refused to see me and he did not see me but with a smile on his face. Ibn Numair has made this addition to this hadith which has been reported on the authority of Ibn Idris that he (Jarir) made this complaint to him (to the Holy Prophet): I cannot sit upon the horse with firmness, whereupon he (Allah's Apostle) struck his chest with his hand and prayed: O Allah, make him steadfast and rightly-guided
Reference: Muslim 6364