God's stated purpose for the tabernacle, priesthood, and sacrificial system was to be continually present among Israel as the one who brought them out of Egypt and thus was their God.
A hasty scan through the extensive instructions for building the tabernacle might result in missing these verses. They articulate the importance of the instructions. It is serious business to have God dwell in the midst of the community. There is concern that God's presence not be episodic. In one sense, it is clear that there is not a literal "exodus from Egypt" every day. But it would also not be desirable to have God merely pop in every once in a while. The tabernacle was to meet the need for everyday continuity ("throughout your generations" [29:42]). The presence of God does not merely trickle down from the priesthood. Aaron and his sons are, indeed, consecrated but here God also meets with the Israelites as well as the priests. God's dwelling among the Israelites is stressed through repetition in verses 45 and 46. The pronoun relationship of the covenant is expressed: "I will be their God." And at the core is the event that grounds the covenant, namely, the exodus from Egypt. All of the specificity around the tabernacle is not to derive something from God. Rather, it grows out of God's desire to dwell among the Israelites.
38 Now this is what you shall offer on the altar: two lambs a year old regularly each day. 39One lamb you shall offer in the morning, and the other lamb you shall offer in the evening; 40and with the first lamb one-tenth of a measure of choice flour mixed with one-fourth of a hin of beaten oil, and one-fourth of a hin of wine for a drink-offering. 41And the other lamb you shall offer in the evening, and shall offer with it a grain-offering and its drink-offering, as in the morning, for a pleasing odour, an offering by fire to the Lord. 42It shall be a regular burnt-offering throughout your generations at the entrance of the tent of meeting before the Lord, where I will meet you, to speak to you there. 43I will meet the Israelites there, and it shall be sanctified by my glory; 44I will consecrate the tent of meeting and the altar; Aaron also and his sons I will consecrate, to serve me as priests. 45I will dwell among the Israelites, and I will be their God. 46And they shall know that I am the Lord their God, who brought them out of the land of Egypt that I might dwell among them; I am the Lord their God.
New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org