Musannaf Ibn Abi Shayba 21:600

Abu Khalid al-Ahmar narrated to us, from Ibn ‘Ajlan, from ‘Umar bin Kathir bin Aflah, from Ibn ‘Umar regarding the lost item: He performs ablution, prays two rak'ahs, recites the tashahhud, and says: "O Guide of the lost and Returner of the lost item, return my lost item to me by Your might and Your authority, for it is from Your gift and Your bounty."