Note: If you want it to sound a little less minor, change the Am to a C at the end 
of the 1st, 4th and 5th lines, like I have in the last verse.

Am (x02210@1)            GEm  Am (x02210@1)O come, O come, Em-man-u-el
     C (x32010@1)           DmG   AmAnd (x02210@1)ransom captive Is---rael
     Dm (xx0231@1)             CEm    GThat (320003@1)mourns in lonely ex--ile here
   Am (x02210@1)           Dm (xx0231@1)G (320003@1) AmUn-til (x02210@1)the Son of God a-ppear
   G (320003@1)       Am (x02210@1)    DmG    AmRe-joice! (x02210@1)Re-joice! Em-man-u-el
        C (x32010@1)         Dm (xx0231@1)Em (022000@1) AmShall (x02210@1)come to thee, O Is--ra-el.

Am (x02210@1)              GEm    Am (x02210@1)O come, Thou Rod of Je-sse, free
       C (x32010@1)             DmG  AmThine (x02210@1)own from Satan's ty--ranny
     Dm (xx0231@1)                C (x32010@1)Em (022000@1) GFrom (320003@1)depths of Hell Thy peo-ple save
     Am (x02210@1)             Dm (xx0231@1)  G (320003@1) AmAnd (x02210@1)give them victory o'er the grave
   G (320003@1)       Am (x02210@1)    DmG   AmRejoice! (x02210@1)Re-joice! Em-man-u-el
        C (x32010@1)         Dm (xx0231@1)Em (022000@1) AmShall (x02210@1)come to thee, O Israel.

Am (x02210@1)                   G (320003@1)Em (022000@1)  Am (x02210@1)O come, Thou Day-Spring, come and cheer
     C (x32010@1)             Dm (xx0231@1)G (320003@1) AmOur (x02210@1)spirits by Thine ad-vent here
     Dm (xx0231@1)            CEm      GDisperse (320003@1)the gloomy clouds of night
   Am (x02210@1)                  Dm (xx0231@1)G (320003@1) AmAnd (x02210@1)death's dark shadows put to flight.
   G (320003@1)       Am (x02210@1)    DmG    AmRe-joice! (x02210@1)Re-joice! Em-man-u-el
        C (x32010@1)         Dm (xx0231@1)Em (022000@1) AmShall (x02210@1)come to thee, O Is--ra-el.

Am (x02210@1)             G (320003@1)Em (022000@1)Am (x02210@1)O come, Thou Key of David, come,
     C (x32010@1)           Dm (xx0231@1)G (320003@1) AmAnd (x02210@1)open wide our heavenly home;
     Dm (xx0231@1)               CEm    GMake (320003@1)safe the way that leads on high,
     Am (x02210@1)            DmG  AmAnd (x02210@1)close the path to mi--sery.
   G (320003@1)       Am (x02210@1)    DmG    AmRe-joice! (x02210@1)Re-joice! Em-man-u-el
        C (x32010@1)         Dm (xx0231@1)Em (022000@1) AmShall (x02210@1)come to thee, O Is--ra-el.

Am (x02210@1)    C (x32010@1)         G (320003@1)Em (022000@1)C (x32010@1)O come, O come, Thou Lord of might,
     C (x32010@1)              DmG     AmWho (x02210@1)to Thy tribes, on Sinai's height,
     Dm (xx0231@1)               C (x32010@1)Em (022000@1)    GIn (320003@1)ancient times did'st gi-ve the Law,
   Am (x02210@1)           Dm (xx0231@1) G (320003@1) CIn (x32010@1)cloud, and majesty and awe.
   G (320003@1)       Am (x02210@1)    DmG    CRe-joice! (x32010@1)Re-joice! Em-man-u-el
        C (x32010@1)         Dm (xx0231@1)Em (022000@1) AmShall (x02210@1)come to thee, O Is--ra-el.

I usually mute the high E string on the G chords, except for in the 5th line of each verse. 
~Enjoy!