Musnad Abu Ya'la al-Mawsili 252:11

Ishaq narrated to us, Sa'id bin 'Abd al-Rahman al-Jumahi narrated to us, he said: Abu Hatim narrated to us, from Sahl bin Sa'd, who heard the Prophet, may Allah bless him and grant him peace, mention Paradise. He said: "In it is what no eye has seen, no ear has heard, and has not occurred to the heart of a human being."