Explaining Eternity

"If you have a steel ball, solid steel, the size of this earth, 25,000 miles in circumference, and every one million years a little sparrow would be released to land on that ball to sharpen his beak and fly away only to come back another million years later and begin again, by the time he would have worn that ball down to the size of a BB, eternity would have just begun." - Chuck Swindoll