Jewish tradition tells of a rabbi who gathered his students together very early in the morning while it was still dark, and asked them this question: ‘How can you tell when the night has ended, and the day has begun?’ One student answered: ‘Maybe it’s when you see an animal and you can distinguish if it’s a sheep or a dog.’ ‘No,’ the rabbi said. A second student answered: ‘Maybe it’s when you are looking at a tree in the distance and you can tell whether it’s a fig tree or a peach tree.’ ‘No,’ said the rabbi. After a few more guesses the students demanded the answer. The rabbi replied: ‘It’s when you look on the face of any woman or man and see that she is your sister, and he is your brother. If you cannot do this, no matter what time it is, it is still night.’