Here are the words to the 3rd verse only, (the first two are in the childrens songbook). 

I wonder when He come again,
Will all the nations bring
Their children to His waiting arms
To hear the angels sing?

And as they heed His loving voice,
And seek His outstretched hands,
Will children of the world rejoice
To finally understand:

That only, as we do His will
Can happiness increase.
That love, alone, can make this world
A haven of His peace?

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Read the hole song: I Wonder When He Comes Again