You're going to hate me for asking the obvious, but best to get it out of the way fast... Are you sure the content is already downloaded (or that you're connected to the internet). From your description, that sounds like the most likely problem.
If it's not that, please power down the device (don't just hit the power button, hold it in and from the popup dialog(s), choose to power off). Wait at least 30 seconds before turning it back on. (I recently had a very peculiar problem with the Gospel Library, and this fixed it - forget what it was though.)
Another possibility would be to go to settings > apps > Gospel Library and clear the cache (I think I'd do this right before rebooting). If worse comes to worst, you could clear the data and re-download everything, but that would really be a last resort.
If nothing else, the next guy can't ask you to do these things...
Liz