Answer
Ezekiel 40—48 describes a future temple and city central during the thousand-year reign of the Messiah. In the final verse of the section (and Ezekiel’s prophecy), the city is called Yahweh-shammah, or The Lord Is There.
Ezekiel introduces the section by describing what he refers to as a structure like a city (Ezekiel 40:2). In that city was a specifically described and dimensioned temple (described especially in Ezekiel 41—42). The glory of the Lord would enter and fill this temple (Ezekiel 43:2–5). God would dwell there and accept offerings and sacrifices there for national cleansing (Ezekiel 43:6–27). Recall that Jesus died for (all) individual people and calls upon all to believe in Him (for example, in John 3:16). It appears that for the nation of Israel to be cleansed as a nation, sacrifices (pointing to Christ) will still be utilized in the millennium. Some have suggested that the sacrifices during this time are simply memorials of what Jesus accomplished with the shedding of His blood. While the text does not expressly answer the question of why these sacrifices were taking place (besides the acceptance of the people as a whole, Ezekiel 43:27), it is clear that the glory of the Lord Himself was there at the temple.
In Ezekiel 45 the focus shifts from the temple to the city. There would be a massive section of the city next to the holy portion (the temple site) that would be designated for the whole of Israel (Ezekiel 45:6). Portions of the land surrounding the city would be designated for one called “the prince” and other princes of Israel (Ezekiel 45:7–8), and the rest of the land would be divided by tribes (Ezekiel 45:8). Water flowed from the temple in this city, becoming a great river that supported trees bearing fruit for food and healing (Ezekiel 47:1–12). The glory and presence of the Lord would be central to all of this, as the Lord is there.
The entire nation—tribe by tribe—would be given allotments of land, and at the center the city would be the focus of life in that land (Ezekiel 48:17–22). There would be four large gates (one for every three tribes) to the north, east, south, and west (Ezekiel 48:30–34). That city would be called Yahweh-shammah, or the Lord Is There (Ezekiel 48:35). Throughout biblical history God communicated that the people descended from Abraham, Isaac, and Jacob were His people and that He would be with them (for example, in Genesis 26:24 and Exodus 19:6).
In time past, God led the people from a distance, but in this kingdom that will one day be established on earth, the Lord will personally be there. When God became a man, He was called Immanuel. That name means “God with us” (Matthew 1:23). Jesus was “God with us.” After Jesus ascended to heaven, He and the Father sent the Spirit of God to be with His disciples and those who believed in Jesus (John 16:5–11 and Acts 2). The Lord is with us today through His Holy Spirit who lives in all those who believe in Jesus (1 Corinthians 3:16). But when Jesus is revealed in glory and comes to establish His kingdom on earth (Revelation 19:13, 20:4–6), the Lord will be on earth living in Jerusalem again. The city Ezekiel saw will rightfully be called Yahweh-shammah, because the Messiah will be there. The Lord is there.
