Musannaf Ibn Abi Shayba 3:5110

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: ‘Ali ibn al-Mubarak narrated to us, from Yahya ibn Abi Kathir, from al-Hadrami ibn Lahiq, from a man from the Ansar, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "If one of you finds a louse in the mosque, let him wrap it in his garment until he takes it out."