Exodus 30 brings us to the end of God's instructions for the construction of the Tabernacle. (Don't worry - you'll get to hear all of these details again when the Israelites actually build it!) This chapter discusses the half-shekel offering required of every man for the maintenance of the tabernacle, the bronze basin for a ritual washing by Aaron and his sons whenever they approach, and the altar of incense and the special anointing oil compound that is to be used only in the Tabernacle - and nowhere else!
God is meticulous in laying down the rules and guidelines for the Tabernacle to impress upon the Israelites that these things are holy - and that God is holy. The idea of separation in the midst of closeness (holiness in the midst of fallenness) is one of the lessons that the Tabernacle teaches.