Your arms like towers: Proverbs 16: 10, Psalm 61: 3, also "Strong Tower" by Kutless.
I am outside/keep me safe inside: pretty self-explanatory. Also, it's interesting to note that it's dark outside, since she's waiting for the sun.
I think the second verse (lock the doors.) is about the narrator hearing God's message and wanting to share it with others (that's why she wants to "capture this voice") and the "show myself it isn't forged/red lights" refer to her occasional moods where she doubts and then proves to herself that it God's words are true.
The "i'll take the truth at any cost" is an amazing statement. I don't know the right word for it.
New favorite song! : D