Musannaf Ibn Abi Shayba 27:510

Ghundar narrated to us, from Shu'bah, from Abu Balj, who said: I heard Mus'ab bin Sa'd narrating that Sa'd had a slave with whom he had a contract of manumission (kitabah). He (Sa'd) wanted something from him, and he (the slave) said, "I do not have what I can give you." He (the slave) then took some dinars and hid them in his sandals. Sa'd invoked (a curse) against him, and his sandals were stolen.