Musannaf Ibn Abi Shaybah

Hazrat Sha'bi and Hazrat Hakam, both state that Ibrahim said: The first person to fix salaries was Hazrat Umar bin Khattab, and he set the full blood money (diyah) to be paid over three years: two-thirds of the diyah in two years, half in two years, and one-third in one year, and if it is less than that, then it must be paid within the same year.