Explicating Chris: Theologically, of course.

There is a candle in every soul
Some brightly burning,
Some dark and cold

A variation on the theme of Pascal's God-shaped hole in every heart. The metaphor holds: we are created to know & love God. And some of us do know him, and so brightly burn; others do not, and so are cold, but still have the potential to know him, which is what the presence of the candle implies. This is a different notion than straight up Calvinism (which, I'll re-assert, Calvin was not party to), which would lean towards saying that there are those within whom there is no candle. That is, the point of the metaphor in this song is that these cold candles have the potential for light.

There is a Spirit who brings the fire

Nice Pneumatology here: it is the Spirit's Fire, and the bringing of His fire is His work, not ours. This is orthodox doctrine, also reformed doctrine. So if the first line leans against Calvinism, this verse leans against Arminianism. Dichotomies which miss the point entirely, imho, but Chris here shoots between them nicely. Let us all live here between them.

Ignites His candle and makes His home

A really great turn of the phrase here. This candle in all of us: it's God's candle. So, in terms of what we bring to the table in this Man/God relationship, it's not very much, according to this song. Not only is the Fire God's to bring and to light, it's God's candle that he's placed in us. And the lit candle indicates that God has now made his home in us. Aesthically speaking, I like the image there. It makes me think of seeing a cabin in the dark woods with light streaming out of the windows. Or, perhaps a bit more Biblical, a city on a hill with light streaming from it in the night.

Carry your candle,

Now it's our candle. Which is right. Because this is both God's candle and our candle. And our response in receiving the candle and it's light is to now carry it. This metaphor is still working: why have a lit candle? Why, to illuminate something/someone. So the right response to being given a candle & light (and so given illumination for self) is to carry said candle to the darkness, which is what Chris turns to in the next phrase. (And, incidentally, why shouldn't the metaphor hold? Christ used it himself!)

Run to the darkness
Seek out the hopeless, confused and torn
Hold out your candle for all to see it
Take your candle and go light your world

Again, a good thing about the song is that it First unequivocally states that this is God's candle, and his work in lighting it, AND that the response is that it's our candle for us to use well.

Frustrated brother,
see how he's tried to
Light his own candle some other way

Theologically sound: we are doomed to frustration by our own work of "self-actualization," "self-discovery," "self-empowerment" and anything else we do to solve this unlit candle problem we've got.

See now our sister,
She's been robbed and lied to
Still holds a candle without a flame

And there are people in this world who will take advantage of others who are looking for a light for their candle. To be told anything other than that the Lord Jesus holds the flame to her candle is to lie & to steal. The worst damage of all is this leads to the belief that their is either no flame for the candle, &/or that there really is no such thing as her candle at all.

We are a family whose hearts are blazing

Beautiful imagery for the body of Christ. Blazing elicits strength, fierceness, power, warmth, and brilliance. Again, Chris has good company here with Christ's imagery of a city on a hill. I'd say this is as good an image for the Church as a "mighty fortress" is for our God.

We raise our candles and light up the sky
Praying to our Father, "In the name of Jesus
Make us a beacon in darkest times!"

We have a trinitarian song here, beginning with the Spirit and ending with an appeal to the Father in the name of Jesus. And while this certainly isn't the only prayer the Church prays, it certainly is an important one, and one that might not get prayed enough.