The Missal by John William Waterhouse
Because it’s a holy text/prayer book, it must be read on your knees. Because there is a fine line between suffering and religious ecstasy. Or because suffering may bring about religious ecstasy?
My prayers (if I still prayed) would be more fervent if I were comfortable. As for reading, I prefer to do so while horizontal. The trouble with this is that these days, being flat on my back means I am fast asleep soon after assuming the position.