[Geekcop]

Since you posted in the 700W/WX subforum, I'm assuming that's the device you've got.
Go into Settings, click on the System tab, then tap the Memory icon. That will give you your available memory readings. Something that eats up a lot of memory is an accumulation of junk files. Get a clean up app such as MemMaid or SKTools to take care of that. You should also look at whether MyBible is in a .cab or .exe format. They're installed differently. The .cab is installed directly on your device, while the .exe is installed to your device via ActiveSync or WMDC