An elder of the people of Makkah from Quraysh says: A man found a louse in his garment and took hold of it in order to throw it in the mosque. the Prophet (peace and blessings be upon him) said to him: "Do not do that; put it back in your garment until you go out of the mosque (and then throw it)."
Ahmad recorded it, and its narrators are thiqat (trustworthy), except that the narrator Muhammad bin Ishaq narrated it with 'an ('an'anah), and he is a mudallis (one who conceals defects in the chain).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2017