Musnad Ahmad 1153:314

Abu Dawud al-Hafari narrated to us, from Ibn Abi Dhi'b, from al-Harith, from Abu Salamah, who said: Aisha said: The Messenger of Allah, may Allah bless him and grant him peace, took my hand and showed me the moon when it rose. Then he said: "Seek refuge in Allah from the evil of this *ghasiq* (darkness/moon) when it settles."