Keep in mind that this movie had a limited release, though. It was only released in 780 theaters opening weekend, and it made an estimated $9,217,013.
The second weekend it played (this weekend) it made an estimated $9,075,000 and actually expanded to 1,178 theaters. It only dropped 1.5%, which is very, VERY low, and very good. Now this may have to do with it showing in more theaters, but still. Most movies drop at least 50% by the second weekend.
So God's Not Dead's actually doing very well.
Here's my source

:
God's Not Dead (2014) - Weekend Box Office Results - Box Office Mojo