Musnad Ahmad 33:1168

'Affan narrated to us, Shu'bah narrated to us, Al-Aswad ibn Qays informed me, from Nabih al-'Anazi, from Jabir ibn 'Abdullah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When one of you enters at night, let him not knock on his family unexpectedly."