In my opinion, this song is about depression.
The first four lines are talking about the general feelings you have in depresiion. You are feeling alone, and no matter how much you seek to feel better, and sometimes even think you found a solution, only to be lent down and go back into depression.
The next two lines are talking to those who are so long inside depression, that they're "torn down" and ironiclly called the "experts at the fall" because they're so used to it.
Next the speaker reaches out to those two kinds of depressed people and tells them they're not alone.
"And this part was for her" I think is talking about how this song is trying to reach the part in a depressed person who's buried deep inside by the hoplessness and emptyness of depression. The song is aimes at the hopefull part which has wishes for the future, however this part is so hidden away that you wonder "does she remember?", does she remember that she's still there? That there's hope?
"It comes and goes in waves" is a perfect description of how depression can feel like sometimes. There are good days, but then, like a sudden wave that comes, you're unable to breath and all lights and hope are gone. After suffering from this for awhile, it can suddenly go away and you can have a few good days out of nowhere. And so it repeats, like waves.
The next four lines are refering to those who are so deep in depression they're "faithless". "Surprised" might mean surprise at either people who try to reach out to them (like the speaker), or at the fact they're still alive. Then the speaker says the strongest line "They're only where they are now Regardless of their fight". Depressed people often are thought of as if they has given up and are not trying hard enough, when in reality they're struggling everyday and are fighting so hard without anyone knowing. The speaker recognizes their fight, and the fact that they're still in this faithless position even though they tried so hard.
Now the speaker is talking to all of those with depression, and tells them they should believe. Most depressed people will think "what for? There's no reason to believe" but the speaker says one does not need a specific reason to believe, you need to believe just for its' sake. I think he speaks about believing in oneself, because you don't need a reason to believe in yourself.
Then again the speaker calls out to all of them and tells them to get up and make beautiful things, like love, because they're capeable of creating those.
"I am only led to wonder why I try" even though it comes and goes with no end. This is a very common thought because it feels like no matter how much you try, even if you're able to fight it once, it will come back eventually. It's a war that can't be won.
In the last paragraph the speaker finally reaches out to those who are asking for help and are trying again and again to fight despite all the faithlessness and the lonleiness he described in the song.
But that's just my opinion :).