Holy smokes.
The gift of prophecy is a gift from the holy spirit,
The prophecy will only come out of your lips because it's being spoken by the holy spirit to somebody who needs help in believing in God. It will be witnessed by two atheists and the prophecy will come true. The atheists will then go on to believe in God.
The prophecy will be spoken to an unbelieving athiest. Once the prophecy has come true the unbelieving person will hopefully believe God is real.
Once the prophecy has been spoken the Gift of prophecy has gone.
If you then go into another place where somebody needs help with believing, the gift of prophecy could come to you again, via the holy spirit speaking through you.
Once the prophecy is finished the gift is gone.
So basically you have recieved a gift and passed it on. But your no longer a prophet until a new gift of prophecy comes.
Let's look to scripture where a born again athiest can also have a prophesy spoke through them from the holy spirit.
All people who feel oppressed please feel to disagree with me.
The born again athiest who speaks a prophesy.
The Parable of the Persistent Widow
18 Then Jesus told his disciples a parable to show them that they should always pray and not give up. 2 He said: βIn a certain town there was a judge who neither feared God nor cared what people thought. 3 And there was a widow in that town who kept coming to him with the plea, βGrant me justice against my adversary.β ( this lady was also praying for God to speak).
4 βFor some time he refused. But finally he said to himself, βEven though I donβt fear God or care what people think, 5 yet because this widow keeps bothering me, I will see that she gets justice, so that she wonβt eventually come and attack me!ββ
6 And the Lord said, βListen to what the unjust judge says (the born again athiest where The spirit had spoke through him.);. 7 And will not God bring about justice for his chosen ones, who cry out to him day and night? Will he keep putting them off? 8 I tell you, he will see that they get justice, and quickly. However, when the Son of Man comes, will he find faith on the earth?β