Sayyiduna Husayl bin Kharijah al-Ashja'i (may Allah be pleased with him) narrated: I came to Madinah with some livestock to sell, and I was taken to the Prophet (peace and blessings be upon him). He (peace and blessings be upon him) said: "I will give you twenty sa' of dates on condition that you guide these companions of mine on the road to Khaybar." So I did that. Then, when the Messenger of Allah (peace and blessings be upon him) reached Khaybar and conquered it, I came, and he (peace and blessings be upon him) gave me those twenty sa'. Then I became Muslim.
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3555