The first five Books of the Old Testament, the Pentateuch sets out the whole scope and plan of Salvation in remarkable order and sequence.
Genesis reveals God Electing and separating a people for Himself. This revelation is cumulative. First, the choice of the
Individual - Abel not Cain, Jacob not Esau. Second, God chose the
Family of Noah for Salvation from the flood, while the rest of mankind perished. Third, He chose the Jewish
Nation to be His peculiar people, separating them from all the nations of the world.
Exodus reveals God Redeeming His elect people, by both Price and by Power. The first-born were redeemed from certain death by the blood of the Paschal Lamb. Israel was redeemed from Egyptian bondage by the Power of God's mighty arm. So the Church of the first-born is redeemed from death by the blood of the Lamb; and God's people are redeemed from the bondage and darkness of the World by the stretching forth of the arm of divine power in delivering them.
Leviticus reveals God's elect, redeemed ones
Worshipping. Israel's worship throughout was founded on Atonement made for them. There was no approach to God except through the shedding of blood to put away sin.
Numbers reveals god's elect, redeemed and worshipping people,
Warring and Wandering in the Wilderness. Their journey to Canaan the Promised Land consisted of pilgrimage and conflict. It still does.
Deuteronomy reveals God's elect, redeemed, worshipping wanderers,
Learning the same lessons over again - Deuteronomy = the law given twice.
So our five colours on the palette are
(1) Genesis shows God's people as Elect.
(2) Exodus as Redeemed.
(3) Leviticus as Worshippers.
(4) Numbers as Pilgrims.
(5) Deuteronomy as Scholars.