Well, I was wrong. Finding an original thought in scripture for subject matter in hymn writing is difficult if not impossible. After 2000 years of hymns perhaps everything has been touched on in some way. The best one can hope is to find a way of expressing a thought in a new way.
The thought that Christ’s sacrifice demands a sacrifice of us is not new in hymnody. Watts has already written about the sacrifice of Christ and points out in When I Survey The Wondrous Cross…
Were the whole realm of nature mine,
That were a present far too small;
Love so amazing, so divine,
Demands my soul, my life, my all.
I don’t know why I didn’t think of that earlier. There are plenty of other examples too.
O well… back to the drawing board.