No foreigner uncircumcised in heart and flesh is to enter my sanctuary, not evern live among the Israellites

Ezekiel 44:1-14

the one facing east, and it was shut. The Lord said to me, “This gate is to remain shut. It must not be opened; no one may enter through it. It is to remain shut because the Lord, the God of Israel, has entered through it. The prince himself is the only one who may sit inside the gateway to eat in the presence of the Lord. He is to enter by way of the portico of the gateway and go out the same way.

Then the man brought me by way of the north gate to the front of the temple. I looked and saw the glory of the Lord filling the temple of the Lord, and I fell facedown.

Say to rebellious Israel, ‘This is what the Sovereign Lord says: Enough of your detestable practices, people of Israel! In addition to all your other detestable practices, you brought foreigners uncircumcised in heart and flesh into my sanctuary, desecrating my temple while you offered me food, fat and blood, and you broke my covenant. Instead of carrying out your duty in regard to my holy things, you put others in charge of my sanctuary. This is what the Sovereign Lord says: No foreigner uncircumcised in heart and flesh is to enter my sanctuary, not even the foreigners who live among the Israelites.

The Levites who went far from me when Israel went astray and who wandered from me after their idols must bear the consequences of their sin. 

Why?
East gate is always closed because this is the gate the Lord comes in, and no one else can go through this gate, and the Lord enters the Temple.

The foreigners cannot go into the Temple and No foreigner uncircumcised in heart and flesh is to enter God's sanctuary. Because only trust in the Lord and obey the regulation of the Lord in heart and flesh may enter.

No foreigner uncircumcised in heart and flesh is to enter my sanctuary, not even the foreigners who live among the Israelites. To be a Christian has to be uncircumcised in heart and flesh. For the Lord is Holy.

The culture of foreigners may influence the people of Israel, so can to allow live among the Israelites.

How?

Keep away the way and mind of this world, the best way is to know the word of the Lord and keep our behavior and mind closer to the Lord.