Musnad Abu Ya'la al-Mawsili 115:180

Abu Musa narrated to us, Mu'adh bin Hisham narrated to us, my father narrated to me, from Qatadah, from Anas, that the Prophet (peace and blessings of Allah be upon him) said: "It will be said to the disbeliever: 'Do you see, if you had the earth filled with gold, would you ransom yourself with it?' He will say: 'Yes.' It will be said to him: 'You were asked for something easier than that.'"