Musnad Ahmad 30:2455

Yahya narrated to us, from Ibn Abi Dhi'b, who said: Sa'id ibn Abi Sa'id narrated to us, from Abu Ishaq, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "No people sit in a gathering without remembering Allah, except that it will be a cause of regret for them. And no man walks a path without remembering Allah, except that it will be a cause of regret for him. And no man goes to his bed without remembering Allah, except that it will be a cause of regret for him." Rawh narrated to us, he said: Ibn Abi Dhi'b narrated to us, from al-Maqburi, from Ishaq, the freed slave of Abdullah ibn al-Harith, and he did not say: "When he goes to his bed."