Textual scholars date the Priestly Source, and the Holiness and Priestly Codes within it, to the late 7th century or later; it appears that before this time, the shaving of the head during mourning was permitted, and even encouraged. The Book of Amos, which is dated by textual scholars to the mid 7th century, as well as the Books of Isaiah and of Micah, which textual scholars date to a slightly later period, portray God as instructing the Israelites to shave their head as an act of mourning: