The order in which the books of the Bible are arranged present a progressive timeline of what God has done in the past with mankind and the nation of Israel, what God is currently doing through the church, the body of Christ today, and what God will be doing again in the future, with and through the nation Israel, when Israel's prophetic kingdom program resumes again.
Genesis is the book of beginnings. There are five critically important beginnings in Genesis chapters 1-12, the last of which is the beginning of a new nation which will be established through the seed of Abraham. That nation will be the means through which God will accomplish his purpose for the earth in accordance with God's two-fold purpose for the universe. In the book of Genesis, we also see the four divine institutions which have been established by God for the successful functioning and orderly maintenance of human society.
In Leviticus 23, Israel's seven feasts provide a remarkable prophetic picture of Israel's calendar of redemption, and in Leviticus 26, Israel's entire history is prophetically outlined in the five courses of punishment which Israel will experience before their kingdom program is ultimately established.
In the book of Numbers, we see how that a lack of faith in Jehovah (by most of the Israelites) to successfully enable Israel to go in and take their promised land results in 40 years of wandering in the wilderness until every one of those faithless Israelites have died off the scene.
Then in Deuteronomy, a new generation is being prepared to go in and possess the land.