Musnad Abu Ya'la al-Mawsili 115:279

Ammar Abu Yasir al-Mustamli narrated to us, Suwayd ibn Ibrahim Abu Hatim al-Hajari narrated to us, Qatadah narrated from Anas, who said: We were with the Messenger of Allah, may Allah bless him and grant him peace, when a flea bit a man, so he cursed it. The Prophet, may Allah bless him and grant him peace, said to him: "Do not curse it, for it awakened a prophet from among the prophets for prayer."