This song of praise is based on a verse from the Book of Psalms in the Old Testament:

As far as the east is from the west,
So far has He removed our transgressions from us.
Psalm 103:12

Casting Crowns is a Contemporary Christian band and one of the most successful gospel bands today.

This song was their first single off their 2007 album The Altar and the Door.

Here I am Lord,
And I'm drowning
In your sea of forgetfulness
The chains of yesterday surround me
I yearn for peace and rest
I don’t want to end up where you found me
And it echoes in my mind,
Keeps me awake tonight

I know you cast my sin as far as the east is from the west
And I stand before you now as,
As though I've never sinned
But today I feel like I'm just one mistake away
From you leaving me this way

Jesus can you show me
Just how far the east is from the west
Cause I can't bear to see the man I've been
Rising up in me again
In the arms of your mercy I find rest,
Cause you know just how far the East is from the West
From one scarred hand to the other.

I start the day the war begins
Endless reminding of my sin
And time and time again your truth is drowned out
By the storm I'm in
Today I feel like I'm just one mistake away,
From you leaving me this way

Jesus can you show me,
Just how far the East is from the West
Cause I can't bear to see the man I've been
Come rising up in me again
In the arms of your mercy I find rest
'cause you know
Just how far the East is from the West
From one scarred hand to the other.

I know you've washed me white,
Turned my darkness into light
I need your peace to get me through,
To get me through this night
I can’t live by what I feel
But by the Truth your work reveals,
I'm not holding on to you
But you're holding on to me,
You’re holding on to me

Jesus you know
Just how far the East is from the West
I don't have to see the man I've been,
Come rising up in me again
In the arms of your mercy I find rest
'cause you know just how far the East is form the West,
From one scarred hand to the other.

Just how far
The east is from the west
Just how far
From one scarred hand to the other

Just how far
The east is from the west
Just how far
From one scarred hand to the other

On this video you can see the lead singer of this rock band (and also Protestant pastor) Mark Hall explaining the meaning of the song:

EAST TO WEST TEACHING VIDEO

Basically, the song says: I had a life of sin but you saved me and now I don't want to fall down again, can you really forgive me? But he knows the answer, God has removed our sins as far as the east is from the west, and that happened because Jesus saved us on the cross, so the distance from east to west is the same as the distance between "one scarred hand to the other" (a reference to Jesus scars from the nails), because from one hand to the other, there is Jesus.

As we said, the song is based on the psalm 103. This is the complete psalm from the Bible:

Psalm 103
   
A psalm of David. Praise the LORD, I tell myself; with my whole heart, I will praise his holy name.

Praise the LORD, I tell myself, and never forget the good things he does for me.

He forgives all my sins and heals all my diseases.

He ransoms me from death and surrounds me with love and tender mercies.

He fills my life with good things. My youth is renewed like the eagle's!

The LORD gives righteousness and justice to all who are treated unfairly.

He revealed his character to Moses and his deeds to the people of Israel.

The LORD is merciful and gracious; he is slow to get angry and full of unfailing love.

He will not constantly accuse us, nor remain angry forever.

He has not punished us for all our sins, nor does he deal with us as we deserve.

For his unfailing love toward those who fear him is as great as the height of the heavens above the earth.

He has removed our rebellious acts as far away from us as the east is from the west.

The LORD is like a father to his children, tender and compassionate to those who fear him.

For he understands how weak we are; he knows we are only dust.

Our days on earth are like grass; like wildflowers, we bloom and die.

The wind blows, and we are gone-- as though we had never been here.

But the love of the LORD remains forever with those who fear him. His salvation extends to the children's children

of those who are faithful to his covenant, of those who obey his commandments!

The LORD has made the heavens his throne; from there he rules over everything.

Praise the LORD, you angels of his, you mighty creatures who carry out his plans, listening for each of his commands.

Yes, praise the LORD, you armies of angels who serve him and do his will!

Praise the LORD, everything he has created, everywhere in his kingdom. As for me--I, too, will praise the LORD.

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J.A. Motyer of Trinity College, Bristol  describes it thus: "The blend of changeless fatherly care and endless sovereign rule (by God) is the distinctive stress of this Psalm."

The most memorable sentence is found in verse 12: "...As far as the east is from the west, so far he removes our transgressions from us..."

The significance of the compass directions being east and west in verse 12, instead of north and south, is that when traveling north you will eventually cross the North pole and begin travelling south, and the same vice versa. This does not happen when travelling east or west, and thus the difference between our transgression and ourselves is considered infinite.