Musnad Ahmad 33:227

Hashim ibn al-Qasim narrated to us, Zuhayr narrated to us, Abu al-Zubayr narrated to us, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Do not let your livestock and your children out when the sun sets, until the darkness of the night (fahmat al-'isha') passes, for the devils are sent forth when the sun sets until the darkness of the night passes."