In his book From Survival to Celebration, Howard Hanchey tells this story:
"Two people were walking along a crowded sidewalk in a downtown business area. Suddenly one exclaimed: 'Listen to the lovely sound of that cricket.' But the other could not hear. He asked his companion how he could detect the sound of a cricket amid the din of people and traffic. The first man, who was a zoologist, had trained himself to listen to the voices of nature. But he didn't explain. He simply took a coin out of his pocket and dropped it to the sidewalk, whereupon a dozen people began to look about them. 'We hear,' said the zoologist, 'what we listen for.' "
Then he makes his point:
"Mission-minded Christians enjoy, more than anything else, the work of listening and looking for signs of God at work in the world. As a result, their common life rings with both a present strength and a future hope."