I have been trying to find the original words, or at least the version I am more familiar with, but cannot find them anywhere. Most have "Mary and Joseph" for the two, and very few of "Paul and Silas." When I was in high school, one of their choir groups, we sang this song--and the words to it are very different than the Christmas one I keep finding. This is how we sang it. (I'm shortening it cuz the song is so long.)

"Children, go where I send thee,
How shall I send thee?
I'm gonna send thee two by two
Two for Paul and Silas
One for the little bitty baby,
the baby boy - born in Bethlehem.

(Repeat in decending order:)

Three for the Hebrew children...
Four for the gospel writers (riders? Not sure.)...
Five for the bread they did divide...
Six for the days when the world was fixed...
Seven for the day God lay down his head...
Eight for the eight that blood couldn't take...
Nine for the angel choirs divine...
Ten for the ten commandments...
Eleven of them singing in heaven...
Twelve for the twelve disciples..."

And how it ended was different too. The four parts split, echoing like there were people crying out the question over and over. Is anyone familiar with this version?
After a visit to my high school next week, I'm going to post this song on YouTube. My choir teacher gave the senior students copies of all the songs we did that year. (I think she does that every year for seniors.)