Abu al-Juwayriyah al-Jarmi (may Allah have mercy on him) narrates: We were in the land of the Romans, and a Companion of the Messenger of Allah (peace and blessings be upon him) from Banu Sulaym, called Ma'n bin Yazid al-Sulami, was appointed as our commander. Abu al-Juwayriyah said: I found a red jar containing dinars, and I brought it to him. He took out a fifth of it and said: Had I not heard the Messenger of Allah (peace and blessings be upon him) say: "There is no extra reward (nafl) except from the fifth (khumus)," I would have given it all to you. The narrator said: Then he offered me something from his own share, but I said: I have no need of it.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17122