Musannaf Ibn Abi Shayba 33:159

Ghundar narrated to us, from Shu'bah, from Sa'd ibn Ibrahim, from Ma'bad al-Juhani, from Mu'awiyah, who said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) saying: "Indeed, this wealth is sweet and green. Whoever takes it by its right, it will be blessed for him."