Voodoo, a religion found in some parts of the American South as well as other parts of the world, has it's origins in the West African religion, Vodun. It is one of the oldest, if not the oldest, living religions in the world, (6,000 years). Many negative myths swirl around Voodoo but these are largely the product of racist stereotypes and/or fear of the mysterious power that does, indeed seem to permeate the practice.
At the center of Vodun are spirits and elemental forces which are believed to rule the earth. It is, however, a monotheistic religion. The creator God, Mawu or Nana Buluku is dualistic, with a male aspect, Mawu, (the Moon), and female aspect, Lisa, (the Sun). These are often depicted as the primary diety's twin children.
There are also Vodun, deities who rule the forces of nature, society and who are the forces behind nature, (streams, trees, rocks). The creator God is not viewed as a being who involves itself with human beings. The Vodun, however, are extremely involved with us. This is somewhat similar to the role played by Saints and Angels in Catholicism.
Vodun has a large pantheon, encompasing a number of traditions. In one of these, primary deities are the seven children of Mawu, who are associated with several tribes, occurrences in nature and historical and mythical people. There are also Vodun associated with different tribes, clans and countries.
In Vodun, everything in the natural world is believed to be part of God. It is a pantheistic religion, believing that all things in nature therefore contain divine power. Mundane objects, as well as powerful plants and herbs, are therefore often considered to be of great significance and play a large part in religious ritual.
The main emphasis of Vodun is on ancestors. Spirits are grouped into families, each with their own priestesshood. The role of priestess is often a hereditary one. Both priestesses/priests and practitioners are believed to become possessed by the spirits routinely during ceremonies. Dancing, drumming and animal sacrifice are central practices.
Essentially, the idea is that the spirits/ancestors/elemental forces are constantly with us, not distant and apart as many religions view their pantheons. They can join us in conversation, dancing, even eating, drinking and smoking and, in Vodun and it's various off-shoots often do. It is important, however, not to anger them. So sacrifices and offerings are made to them and their advice or direction is considered best heeded.
It is believed that the will of the spirits can be seen in everyday occurrences and events. When good things happen, it can be assumed that their will is being followed and/or what they have been asked for has been given and they have been appropriately thanked. When bad things happen, the opposite can be inferred.
Reference: spellscasting.blogspot.com