I know the Boney M version has been posted but this is the Melodians'. It was a genius bit of editing. It is mostly based on Psalm 137 of the Old Testament. That psalm has a horrific ending about killing the children of their captors, but they replaced that bit with bit from Psalm 19, which goes, "Let the words of my mouth, and the meditation of my heart, be acceptable in thy sight." Brilliant.
And here's another take on psalm 137