Needtobreathe is an American Christian Alternative rock band from Seneca, South Carolina. This song was released as a radio single at the end of 2007, becoming a #1 hit in the spring of 2008. It was the sixth most-played song on R&R's Christian CHR chart for 2008.

Daddy was a preacher
She was his wife
Just tryin' to make the world a little better
You know, shine a light

People started talking
Just to hear their own voice
Those people tried to accuse my father
Said he made the wrong choice

Though it might be painful
You know that time will always tell
Those people have long since gone
My father never failed

Even when the rain falls
Even when the flood starts rising
Even when the storm comes
I am washed by the water
Even when the rain falls
Even when the flood starts rising
Even when the storm comes
I am washed by the water

Even when the Earth crumbles under my feet
Even when the ones I love turn around and crucify me
I won’t never ever let You down
I won’t fall
I won’t fall
I won’t fall as long as You’re around me

Even when the rain falls
Even when the flood starts rising
Even when the storm comes
I am washed by the water
Even when the rain falls
Even when the flood starts rising
Even when the storm comes
I am washed by the water

Even when the rain falls
Even when the flood starts rising
Even when the storm comes
I am washed by the water
Even when the rain falls
Even when the flood starts rising
Even when the storm comes
I am washed by the water

YOU KNOW= Most of the times this is just a filler that means nothing, very used in colloquial conversation, and really overused by some people, especially when they’re nervous or don’t really know what to say:
- I went to this house and, you know, nobody answered the
- Well, you know, I think today I gonna have a rest cause, you know, I feel so lazy and all that, you know. So, errm… you know, I was kind of thinking that maybe… you know… just maybe you could just come and, you know, have a drink with me at home or something.
It may also be just a polite way of explaining something making the other person feel that I suppose they already know it:
- I went to the capital of Cambodia, you know, Phnom Penh (I’m quite sure you didn’t know what the capital of Cambodia is, but I didn’t want to make you feel stupid or ignorant)
But we can also use this expression just for the opposite, when we think the listener probably understands what we’re talking about, but just in case, we’re going to say it in a different way to make sure they understood:
- I love Malaga, you know, that city in the south of Spain.
In this example, “you know” might just be nothing, as we said above, or it might refer to “I love Malaga” so “I suppose you know that I love Malaga”; or it might refer to “Malaga” so it would mean “you know that Malaga is a city in the south of Spain, but I tell you just in case you don’t know where Malaga is”.
- It’s a Mercedes, you know, one of the best car brands in the world (here we’re explaining what a Mercedes is, just in case the listener doesn’t know)
So in this song he says that his father was…
… Just trying to make the world a little better. You know, shine a light.
To shine a light is to bring a light into the darkness, so metaphorically it means to make the world a better place. So that sentence in the song is using “you know” to better explain the meaning of something by rephrasing the idea with different words, though he knows that all his listeners (his native listeners) know perfectly well that to make the world a better place is the same as to shine a light (so we could just consider this an emphatic construction)

THEIR OWN VOICE= Their voice (here “own” is emphasizing because it means “belonging to them”)

YOU KNOW THAT TIME WILL ALWAYS TELL= … will always tell the truth. It means that in time, the truth is always revealed and lies are known to be lies.

FAILED= In this context “fail” means “falter”. To falter is to hesitate, to be unsure of what to do. More exactly they refer to his father's faith.

FLOOD= /flʌd/ The inundation of land (when water covers the land) through the overflowing of a river or something, for example when it rains very very much.

I AM WASHED BY THE WATER= For Christians, the water is a symbol of the grace of the Holy Spirit (God’s protection) because it is associated with baptism. So to be washed by the water is a metaphor they use to say “I feel God’s presence and protection with me”. The dove they're drawing on the video is the usual representation of the Holy Spirit.
NOTICE that the song is the sons talking about their father, but here in the chorus (even when the…), it is the father talking, so first they said “he” but know they say “I”.

CRUMBLES= Falls down. If something crumbles it breaks into pieces and falls down, it’s destroyed.
The expression to feel the earth crumble under your feet refers to those moments when you feel all your life is destroyed, everything that was secure and solid in your life, is shaken and you feel lost and vulnerable because the situation radically changed for the worse.

WHEN THE ONES I LOVE TURN AROUND AND CRUCIFY ME= This pastor (preacher/priest) loved his congregation (people attending his church), but those people suddenly (for some reason we are not told) TURNED AROUND (totally changed their affection or ideas) and CRUCIFIED HIM. To crucify someone is to reject him and destroy his life (a metaphor drawn from Jesus’ crucifixion). If we say that “they crucified him”, we mean that people (usually everybody around you, not just a few) reject you and cause you problems. So here they’re talking about how his father was betrayed by those who he loved, by his congregation.

LET YOU DOWN= Disappoint, fail to meet your expectations, abandon you. This “You” refers to God.

The song was written by the Rinehart brothers about their father who was a pastor. Lead singer Bear Rinehart said,

"It's a song about my dad. He's a pastor...There was some stuff that got said at our church that actually turned out to not be true when it all came out. I just thought it was a cool thing that my dad kept his integrity throughout that whole situation. Yeah, and we put sort of a gospel feel to it. There's a gospel choir on the record that we recorded. And yeah. It's one of my favorites too."

The song talks about a man (their father) who must face a terrible situation but he sticks to his faith to survive through it:

Even when the rain falls
Even when the flood starts rising
Even when the storm comes… I AM WASHED BY THE WATER

It is God who gives him the strength to confront all the attacks against him without breaking. The expression “washed by the water” is a reference to Christian baptism (when you are submersed into water or water is poured over your head) and at that moment you are filled with the Holy Spirit (God). So basically, the chorus says, I feel God’s grace (God’s protection) inside me even when everything around me is powerfully destructive.