Musnad Ahmad 1253:1

Abdullah ibn Yazid narrated to us, he said: Sa’id—meaning Ibn Abi Ayyub—narrated to us, he said: Abu al-Aswad narrated to me, from al-Nu’man ibn Abi ‘Ayyash al-Zuraqi, from Khawlah bint Thamir al-Ansariyyah, that she heard the Messenger of Allah (peace and blessings of Allah be upon him) saying: "Indeed, the world is sweet and green, and indeed, there are men who delve into the wealth of Allah without right; for them is the Fire on the Day of Resurrection."