Pray is always a verb. Its main definitions are (1) to utter a prayer to a god another higher power, and (2) to make a fervent request. Prey is a noun meaning one that is hunted or attacked and a verb meaning to hunt, catch, or eat as prey. These homophones are easily confused.
Examples
For example, the following writers mix them up:
And it’s unfortunate that they seem to pray on the most vulnerable of our population. [Daily Freeman Journal]
… they had better start preying to the ghosts of the 1942 Toronto Maple Leafs and 1975 New York Islanders. [The Observer]
And these writers use the words well:
Others compare drought to a python, which slowly and inexorably squeezes its prey to death. [New York Times]
They, evidently, agreed that I ought not to pray in the church basement nor to pray on the church grounds. [Marshall Independent]
An unemployed man from Utah is advertising himself as the prey for hunting enthusiasts for $10,000. [Independent]
Two weeks away from the federal government defaulting on its debts — how, pray tell, has this come to pass? [CNN]
