The scope and connection of Leviticus and Numbers
The Book of Leviticus contains the revelation of God sitting upon the throne, where He places Himself that He may be approached by the people, as far as they could come; that of the priesthood brought into proximity to the throne, as far as men could have access to it; and then the promulgation of the commandments relative to these two great facts, in that which concerned the generality of the people.
In Numbers we have the service and walk of the people, figuratively of the saints through this world: and, consequently, that which relates to the Levites, and the journey through the wilderness. Now, as Leviticus ended with regulations and warnings respecting the possession of the land, and that with regard to the rights of God, and consequently to the rights of His people, the Book of Numbers brings us through the wilderness to the moment before the entrance of the people into the land at the end of the wilderness journey, and speaks of that grace which justifies the people at the close, notwithstanding all their unfaithfulness.
The wilderness journey
It is important to keep in mind that as to the efficacy of redemption the people were brought to God at Sinai (Ex. 15:13; 19:4). All in this respect was complete (compare the thief on the cross and Colossians 1:12). The wilderness journey is a distinct thing; no part of the purpose of God, but of His ways with us. Hence it is here “if” comes in and the time of testing. Jordan coalescing with the Red Sea, coming out and going in (only the ark was in Jordan), there was no question of judgment or enemies. It is the experimental realization of our death and resurrection with Christ. But as to the journey we must reach the goal to get in.