Musannaf Ibn Abi Shaybah

Hazrat Umar bin Katheer bin Aflah narrates that Hazrat Ibn Umar (may Allah be pleased with them) used to say regarding a lost item: Perform ablution and offer two units of voluntary prayer, and recite the testimony of faith and these words: "O the One who guides those who are lost by Your name, and the One who returns the lost. Return my lost item to me by the means of Your honor and sovereignty. For it was only by Your grace and bounty that I had received it."

Hazrat Mujahid says that Hazrat Ibn Abbas (may Allah be pleased with them) said: Indeed, besides the guardian angels, Allah has some additional angels. When a leaf falls from a tree, they write it down. So when any of you faces any hardship during a journey, call out these words: Help of Allah's servants. May Allah have mercy on you.