Religion works expressively with symbols and metaphors, images that reflect and explain a metaphysical world, a world that transcends the primary senses and it is addressed to the mind and spirit. In time, church has defined and used symbols that now have obvious meaning for the practicing believer. "To read" a church logo you need to be aware of the meaning of the metaphors used, you need to be familiar with the icons in order to decipher the message.
In time, church used simple images, familiar, day to day symbols that believers could remember and associate new meaning to. It used stories to create and associate meaning to simple objects or things. Thus a cross has turned from an element of torture into an symbol of hope, a fish became a sign of christian gatherings, a crown is an image of eternal reward, the crown of thorns represents the Saviour, a dove is an image of Holy Spirit and a book represents the Word of God, while a man with his hands up describes reverence and worship.
To design a church logo you have to understand the inside information and the exact meaning of the symbols. Furthermore, you need to understand the characteristics of a certain denomination and the things that are important for that specific group of people. I've made a selection of beautifully designed church logos to research the way different symbols are integrated and the way they tell a certain story.