Musannaf Ibn Abi Shayba 13:1983

Abu Bakr narrated to us, he said: Ad-Dahhak bin Makhlad narrated to us, from Ibn Jurayj, he said: Ibn Abi Mulaykah informed me that Umar bin Abdul Aziz decreed regarding the reward for a runaway slave, if he is captured at a distance of three [days' journey], that it is three dinars.