He proceeded to drop the chalk, but as he did, it slipped out of his fingers, off his shirt cuff, onto the pleats of his pants, down his leg, and off his shoe.
As it hit the ground, it simply rolled away, unbroken.
The professor's jaw dropped as he stared at the chalk.
He looked up at the young man and then left the lecture hall.
The young man who had stood up proceeded to walk to the front of the room and shared his faith in Jesus for the next half hour.
300 students stayed and listened as he told of God's love for them and of his power through Jesus.