Musnad Ahmad 33:781

'Affan narrated to us, Hammad ibn Salamah narrated to us, he said: Habib al-Mu'allim informed us, from 'Ata', from Jabir ibn 'Abdullah, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Keep your children indoors until the heat of the night (the first darkness) passes, for it is an hour in which the devils spread out."