Not really off topic as I need it to play on my whistle. I can’t find any music for ‘Oh Lord my God, How good thou art.’ I hope that’s the correct words as I have search3ed for about anhour through old books etc. One of the trumpets was playing it in our band the other night and I want to play it as well. He didn’t have the music. 
The real name of that hymn is “How Great Thou Art”. That might help in your searches. I could write down the notes for you if you’re having trouble locating music for it.
Harriswhistles
I couldn’t find it either. This is where I usually look for hymns: www.cyberhymnal.org
OK, I guess there is another hymn called “O LORD MY GOD! HOW GREAT ART THOU!” My mistake. The hymn “How Great Thou Art” of course begins with the words “O Lord My God”, but appears to be a different hymn. Here’s a link to the hymn you were asking about at CyberHymnal:
That’s it. Thanks a lot.
OHMIGOSH! The words were written by John Q. Adams - 6th President of the United States!
That would mean… that there was a… CHRISTIAN HYMN WRITER IN THE WHITE HOUSE! How did the Republic survive?
Even funnier is that mymarried name was Adams!!!