Hosanna, Blessed be the Rock
Arr by Lisa

Here's how I play it (never heard it on a recording, just how my choir sang it to me)

C/C to F I rock those chords back and forth keeping the C in the L.H.- I will call upon the Lord for
F - He is
Em7 - worthy to be
Dm7 - praised
G7 - filler
same thing again (can't remember the words  
the chorus goes

G7 (pick up) Ho-
C -sana
F - bless it be the
C - rock
F - bless it be the
C - rock of my sal-
Dm7 - va-
G7 tion - Ho-
C - sana
F - bless it be the
C - rock
F - bless it be the
C - rock of my sal-
Dm7 - va-
G7 - a
C - tion

the I go Ab7 to modulate to Db

and so on. I keep modulating just the chorus until we get to Eb then end.

Ab7 is the 5 chord in the key of Db. 5 leads to the one chord. So for the key of D, you will play an A7 chord to
go to D, then a Bb7 chord to go to Eb.