I've watched The Oak Ridge Boys' version, and it sounds quite different from the "original" gospel versions I have heard, even the chorus.

The Mouskouri lyrics posted above are close to the versions I have heard by gospel singers like Mahalia Jackson and Sister Rosetta Sharpe. You can find videos on youtube.

Thanks for the lyrics!

Didn't It Rain
------Nana Mouskouri

Didn't it rain children
Talk about rain oh my Lord
Didn't it fall didn't it fall
Didn't it fall my Lord didn't it rain

Didn't it rain children
Talk about rain oh my Lord
Didn't it fall didn't it fall
Didn't it fll my Lord didn't it rain

Oh it rained forty days
And it rained forty nights
There was no land no where in sight
God send the angel to spread the news
He haste his wings and away he flew
To the East to the West
To the North to the South
All day all night how it rained how it rained

Didn't it rain children
Talk about rain oh my Lord
Didn't it fall didn't it fall
Didn't it fall my Lord didn't it rain

Some at the window some at the door
Some said Noah can't you take a little more
No no said Noah no no my friends
The nature got to keep you can't get in
I told you I told you a long time ago
You wouldn't hear me you disobey me
Lord send the angel a warning to you
It began to rain and now you are through

Well it rained forty days
Forty nights without stopping
Noah was glad
When the rain stopped dropping
Knock at the window knock at the door
Come on brother Noah
Can't you take any more
No no my brothers you are full of sin
God has the key you can't get in
Would you listen how it rained

Didn't it rain children
Talk about rain oh my Lord
Didn't it fall didn't it fall
Didn't it fall my Lord didn't it rain

Didn't it rain children
Talk about rain oh my Lord
Didn't it fall didn't it fall
Didn't it fall my Lord didn't it rain

Recent son by the Oak Ridge Boys , " didn't it rain children, didn't it rain, rain, rain, 40 days and nights didn't it rain"