"God Was Busy" joke

A college professor, an avowed Atheist, was teaching his class.
He shocked several of his students when he flatly stated that there is no God, the expression "One Nation Under God", was unconstitutional, and further, he was going to prove there is no God.
Addressing the ceiling he shouted: "God, if you are real, then I want you to knock me off this platform. I'll give you 15 minutes!"
The lecture room fell silent.
You could have heard a pin fall.
Ten minutes went by.
Again he taunted God, saying, "Here I am, God. I'm still waiting."
His countdown got down to the last couple of minutes when a Marine just released from active duty and newly registered in the class walked up to the professor, hit him full force in the face, and sent him tail over teacup from his lofty platform.
The professor was out cold!
At first the students were shocked and babbled in confusion.
The young Marine took a seat in the front row and sat silent.
The class fell silent... waiting.
Eventually, the professor came to, shaken.
He looked at the young Marine in the front row.
When he regained his senses and could speak he yelled, "What's the matter with you? Why did you do that?"
"God was busy. He sent me."