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.
You might have heard of alphabet color pages that are used to teach preschool kids and toddlers. They are taught alphabets and relate them with their surroundings. Similarly the Biblical coloring pages are there too for getting direct print from your computer and show them to your children. The world of web has been really delightful in these matters. You can find ready made color pages in hundreds of styles and colors that also contain Biblical themes, stories like Noah's Ark, the Whale, miracles of Jesus, about the birth of baby Jesus, Mother Mary, Easter, Gift of Magi and alike. The use of these coloring sheets is perfect to teach preschool children the values and morals of Christianity, the true meaning of religion and how to become pious.