Various simple Biblical coloring book pages actually celebrate the life of Jesus Christ and the apostles pages show Christ in different ages of - adolescent, youth, adult and his ending days. The parables pages are good coloring pages to relate with the stories of Bible.
With online printable coloring pages you never have to keep volumes of coloring books around. Most children change what they would like to color often. They bounce around from one theme or one set of characters to the next. Therefore they may abandon that coloring book with princesses or cars days after you buy it. Printing out the pages though allows them to always get what they want.