The word "citadel" takes its root from "city". The citadel, however serves the purpose of outfitting and armoring an otherwise defenseless place. It's not enough to have a city. You have to know how it functions, its rhythms and flow. Day and night and night and day. And how to defend it. There's something about a bustling downtown metropolis just waking up. The mist rising from the manhole covers. The angular light from the sunrise glinting down a deserted alley. The city has a mystique all its own. And I think that's what Jesus is hinting at when He says in Matthew's gospel (5:14) "Ye are the light of the world. A city that is set on an hill cannot be hid." Did he just call me a city? Or is He talking just to me? I think He's levelling His statement at His Body. But taking the symbolic approach to the world with reference to us, we as a race don't seem to have gotten much further than "the city". And so, I think it's a good place to start.
"Now the city was large and great: but the people were few therein, and the houses were not builded." (Nehemiah 7:4)
It's referring to Jerusalem after the massive rebuilding project of its walls. Something in which everyone partook. It says in chapter four, verse seventeen, that "every one with one of his hands wrought in the work, and with the other hand held a weapon." That might sound drastic, but the cohesion of the church as a body of believers--something resembling its founding in the Book of Acts--can be so, so hard to maintain let alone find. I wonder if we really care about the station of the people we see on Sunday morning. They are what makes up the city in which we find ourselves. The closeness of God's children to one another (and Him) is supposed to be so markedly different than any other group that it's supposed to be seen. As Jesus says, it "cannot be hid". But unless we are able to keep out the lies that would tear down walls and tear us apart, we won't coalesce into something greater than the sum of ourselves.
"He that hath no rule over his own spirit is like a city that is broken down, and without walls." (Proverbs 25:28)
It starts in our own heart and mind. Knowing God there first and in turn sharing Him with others, is the key to the city. And like Jerusalem, the more people do this--building their own houses, as it were--the more we can form up and follow suit.
"And I John saw the holy city, new Jerusalem, coming down from God out of Heaven, prepared as a bride adorned for her husband." (Revelation 21:2)
The whole point of God creating anything is to form an outward reflection of Him as a person. From water to earth to a building and to a city. God's word is replete with the symbolic--because that's all that we can do. God is like this. Like that. And He loves you. Don't forget that. Strip away the symbolic and you have to do away with this plane. Because what else do we have to work with? Without sounding apocalyptical, if there's nothing on this earth, not you, me, anything that would get someone to look to God and maybe try on belief in Jesus as Savior and friend, where else will you go? There is nowhere else.
"Behold, what manner of love the Father hath bestowed upon us, that we should be called the sons of God: therefore the world knoweth us not, because it knew Him not." The second verse of the third chapter of John's first letter. He continues in the next verse: "Beloved, now we are the sons of God, and it doth not yet appear what we shall be: but we know that, when He shall appear, we shall be like Him; for we shall see Him as He is." (emphasis mine)
Maybe this is why there'll be a "new Heaven and a new earth" (Revelation 21:1)?