The book of Deuteronomy (sefer Devarim) is considered the composite of two layers of redaction, 'D1' and 'D2.' Together, these layers (commonly referred to as the 'Deuteronomist') are thought to have formed by a complex process that reached probably from the 7th century BCE to the early 5th. In general, D2 shares a particularly non-Judean perspective following the split between the north (Ephraim/Israel) and the south (Judah) after the reign of Solomon, a perspective that was ignored by D1 (and successive authors). D2 thus adds a parallel summary of the Northern Israelean monarchs, and brings in the prophetic narratives of Elijah and Elisha which take place in Northern Israel during the time of the Northern Israelean monarchy. In Deuteronomy, D2 adds hortatory (sermons) to D1’s narrative introduction at the beginning of Deuteronomy (the focus of which is the observation of the commandments and divine justice), and otherwise supplements D1’s work. D2 also adds some verses to the book of Exodus (sefer Shemot) in Parashat Bo.