There's an interesting story benihd this one Protestant church music of the day was either traditional or based in scripture. Calvin and Luther based their songs on Scripture as a rule, so when Isaac Watts began to write on subjects outside of Scripture, some segments of the congregation did not like it, and would walk out in protest.So the words, Let those refuse to sing/Who never knew our God take on a whole new meaning in this light

From our 2010 Archives:
http://www.namethathymn.com/hymn-lyrics-detective-forum/index.php?a=vtopic&t=8233

Come, we that love the Lord,
And let our joys be known;
Join in a song with sweet accord,
Join in a song with sweet accord
And thus surround the throne,
And thus surround the throne.

Refrain
We're marching to Zion,
Beautiful, beautiful Zion;
We're marching upward to Zion,
The beautiful city of God.
Let those refuse to sing
Who never knew our God;
But children of the heav'nly King,
But children of the heav'nly King,
May speak their joys abroad,
May speak their joys abroad.


Refrain
We're marching to Zion,
Beautiful, beautiful Zion;
We're marching upward to Zion,
The beautiful city of God.
The hill of Zion yields,
A thousand sacred sweets
Before we reach the heav'nly field,
Before we reach the heav'nly field
Or walk the golden streets,
Or walk the golden streets.


Refrain
We're marching to Zion,
Beautiful, beautiful Zion;
We're marching upward to Zion,
The beautiful city of God.
Then let our songs abound,
And every tear be dry;
We're marching thro' Immanuel's ground,
We're marching thro' Immanuel's ground,
To fairer worlds on high,
To fairer worlds on high.


Refrain
We're marching to Zion,
Beautiful, beautiful Zion;
We're marching upward to Zion,
The beautiful city of God.

We're Marching, Marching Up to Zion