One common question that comes up in modern Wiccan and Pagan practice is that invoking a deity, as opposed to evoking the deity. The words are similar, as are their meanings, but they are not interchangeable by any means.
To evoke a deity or being is to call upon it and ask it to join you during ritual or a working. Sometimes this involves simply asking (“Hail, Ares, we ask you to join us in the circle tonight!”) or making an offering (“Great Brighid, we offer you this bread as a gift of thanks!”) in hopes that the deity will turn up. Regardless, evoking is an external involvement with the deity or being.
Invoking, on the other hand, is a form of voluntary possession. When you invoke a deity or being, you’re not asking it to come hang out, you’re inviting into yourself, and that god or goddess will manifest through a human host. The ritual of Drawing Down the Moon is an excellent example of invocation of deity.
Typically, if you’re new to spiritual practices such as Wicca or Paganism, most people will advise you to hold off on invoking deity until you’ve learned enough to have a good handle on what’s happening. It may be a good idea to focus instead on evoking, and communing with the gods, before you go inviting them to take control of you, even if it is just on a temporary basis.
The Three Circles Coven performed a house blessing ritual, evoking Brighid as goddess of hearth and home, and honored her with song and offerings.
Willow invoked the goddess Selene when she performed a Drawing Down the Moon ritual, allowing the deity to speak through her body.