Lyric discussion by Moromillas 

Cover art for Crosses lyrics by José González

"Don't you know that I'll be around to guide you, through your weakest moments, to leave them behind you."

That sounds like what a father would do for their son, or daughter.

"Returning nightmares. [They're] only shadows (They're not real). We'll cast some light and you'll be alright. We'll cast some light and you'll be alright, for now."

This depicts a very vivid scenario. Of a father coming to the aid of his son, who is having nightmares.... Re-assuming him that it's just a nightmare, and that it's not real. Telling him not to worry, that he'll just cast some light, and you'll be alright. Along with the ominous "for now," as nightmares are the least of your worries in life.

Next he sings about "Crosses", or the burdens that his son (or daughter) will have in their life. And each time that the child has more "Crosses" growing up, he always comes to help his child. It always ends with a "Don't worry, we'll cast some light and you'll be alright." Just like it was having nightmares as a small child. Because that's just how far a parent's love extends. That's just what they do.

My Interpretation