I first heard "What Wondrous Love is This" many years ago when we sung it in a college choir.  There are many videos of this simple but beautiful hymn.

This song has been associated with the Appalachian area.  It has been passed down through the generations and exists in several different versions.  The repetition of key phrases such as "oh, my soul' and "I'll sing on" helps in memorization.  In 1835, it is said to have first appeared in a collection titled "Southern Harmony" by William Walker.  

The bluegrass in this video helps me to think of the roots of the song.  There is another verse often sung that is not on the video:

To God and to the Lamb I will sing, I will sing:

to God and to the Lamb I will sing;

to God and to the Lamb who is the great "I Am," 

while millions join the theme, I will sing, I will sing;

while millions join the theme, I will sing.

Wikepedia list six original verses.  The two other verses are:

Ye winged seraphs fly, 

Bear the news, bear the news!

Ye winged seraphs fly

  Bear the news!--

Ye winged seraphs fly, like comets through the sky,

fill vast eternity! 

with the news, with the news!

Fill vast eternity with the news!

Ye friends of Zion's king,

join His praise, join His praise.

Ye friends of Zion's king,

join His praise.

Ye friends of Zion's king, with hearts and voices sing,

and strike each tuneful string

in His praise, in His praise!

and strike each tuneful string in His praise!