The song is really in the key of "Eb" but this is a whole lot easier.
I'll probably make a chart in the key of "E" soon to make it easier for some people
Chords:

Dsus2   Csus4    G/B
xx---- x---O- ------
xx-O-- x----- -O----
xx--OO xOO--- -----O
xx---- x----- ------

Verse1:
              D    Dsus2   D                  D     Dsus2       D
What if the armies of the LORD picked up and dusted off their swords and 
          G        Csus4     G               Bm    G        D
vowed to set the captives free and not let satan have one more what if the 
 D           G       D                      G       Bm                 G
church for heaven's sake finally stepped up to the plate took a stand upon 
       D            G             G/B      D
God's promise and stormed hell's rusty gates

Chorus:
                           A Bm G
What if his people prayed 
                    Bm   A
And those that bear his name 
                         A   Bm   G
would only seek his face yeah
                    Bm   A
and turn from their own ways

Verse 2:
                D    Dsus2    D                           Dsus2     D
And what would happen if we prayed for those raised up to lead the way and 
       G       Csus4         G                Bm          G        D
maybe kids in school could pray and unborn children see light of day. What 
        D         G      D                     G       Bm     
if the life that we pursue came from a hunger for the truth what if the 
        G         D                    G     G/B     D 
family turned to Jesus stopped asking Oprah what to do.

Chorus:
                           A Bm G
What if his people prayed 
                    Bm   A
And those that bear his name 
                     Bm   G
would only seek his face yeah
                    Bm   A
and turn from their own ways
               Bm       G        
he's answered loud and clear yeah
            Bm     A
if only we would pray.