Like "practice" and "practise", "prophecy" is the noun and "prophesy" the verb. The last syllable of the verb is pronounced "sigh". There is no verb "to prophesize".
The witches in Macbeth prophesy that "No man born of woman shall harm Macbeth", but this prophecy is intended to deceive.
In today's Globe, we read in a review of a modern derivative of the play, that
Bearing news of the witches' prophesies, [the letter] was somewhat carelessly left lying around...
The reference should, of course, be to the witches' prophecies.
More serious is the error in an article on the Paris Fashion Week in the Globe of March 18, 2011.
"Everything is changing," prophesized the designer post show.
This should read:
"Everything is changing," prophesied the designer post show.