God shows Ezekiel the outer, east-facing gate of the sanctuary. He says that this gate is supposed to stay closed since he (God) has entered by it. Only the king will be allowed to sit in the gate and eat. He'll enter by way of the gate vestibule and go out the way he came.
Then God brings him to the north gate, where Ezekiel falls on his face again when he sees God's glory filling the Temple.
God tells Ezekiel to listen up, because he's about to give him the straight dope on the Temple's ordinances and laws.
He orders the people to stop admitting foreigners—"uncircumcised in heart and flesh"—to the Temple when they're offering fat and blood to God. They'd even allowed the foreigners to take charge of the sacrifices at times.
So no foreigner, uncircumcised in heart and flesh, can enter the sanctuary.
A Stick for the Levite Priests and a Carrot for the Zadokites
As punishment for straying from God and helping people serve idols in the past, the Levite priests will only be allowed to have oversight at the gates of the Temple, serve in the Temple, slaughter the burnt offering, attending on and serving the people.
But they won't be allowed to come near God or the sacred offerings.
So basically, they're just going to have to do all the Temple chores.
But the levitical priests descended from Zadok will get a much better deal. They'll be allowed to come close to God and offer him sacrifices.
When they enter the inner court, they need to wear linen vestments and definitely nothing made of wool. They'll have linen turbans, linen undergarments, and won't wear anything that make them sweat.
They'll remove their holy vestments when they go into the outer court where they'll wear something else. The vestments will be stored in the holy chambers.
This is so they don't accidentally consecrate people who might come in contact with them. Holiness is transmittable by casual contact, we guess.
Priestly Bro Code
These priests will only trim their heads and won't shave their heads. Absolutely no dreadlocks in this Temple.
They won't drink wine in the inner court and won't marry a widow or divorcee. They'll only be allowed to marry a virgin from the house of Israel or the widow of a priest.
They'll teach the people to distinguish between holy and common, clean and unclean.
They'll act as judges and make sure to keep the laws for the festivals and Sabbaths.
They won't be allowed to defile themselves by going near a dead person, unless it's a close family member (mother, father, son, daughter, brother, or unmarried sister). But even after that he needs to become clean, wait seven days, and then make a sin offering.
God will be the inheritance of these priests, and they'll eat the grain offering, the sin offering, and the guilt offering.
They'll get all the different kinds of first fruits, and the first baked goods, which the people will give so that there'll be a blessing on their houses. Those with the best brownies will get the most blessings.
The priests can't eat anything that died by itself or was torn by animals.