Make no apologies for subject requirements but learn to choose popular biblical or religious topics. The reason for this advice will soon become self-evident to your staff when they receive only a few entrees, if any. Protestant artists do not ordinarily produce religious art works these days. Most of them, if they submit appropriate work at all, will need time to create something special for your exhibit. There are many common topics still circulating among artists that are not thought to be terribly ''Biblical" but in fact are. Anticipate the interests and submissions by  monks and nuns who wish to participate in your churches exhibits. They may be the only artists in your community to have works already available under the following subjects or more elaborate ones, if you live in America. In Great Britain there are many illuminators that are both Protestant and well versed in traditional depictions of Biblical subjects. These creative people may be called upon to help organize your efforts and thinking if you find yourselves in a real bind. 
   Here is a list of Biblical and historically religious topics that many artists still produce no matter what church they attend and sometimes they are quite unaware of the religious or biblical roots of these subjects. Indeed these subjects may show up in the works of non-Christian believers as well.
  1. Tree of Life
  2. Noah's Ark
  3. Dove of Peace or The Holy Spirit in the form of a Dove
  4. The Peaceable Kingdom
  5. St. Francis of Assisi and his animal friends
  6. Rainbows
  7. Angels of any kind
  8. Nativities
  9. Jesus and the children
  10. The Cross
  11. Grapes and wheat or wine and bread
  12. The lion and the lamb
  13. The All-Seeing Eye

Note. The only way to navigate around this problematic situation concerning the lack of education in Christian art subjects is to alternatively assign a subject to a group of committed artists months in advance. This can be seen as a natural goal for any fine arts ministry. Many artists paint for an exhibit in high school, college or when they join a coalition or artist community. Indeed many of them will anticipate an exhibit at the end of a certain period of learning.