A Rabbi gathered together his students and asked them:
‘How do we know the exact moment when night ends and day begins?’
‘It’s when, standing some way away, you can tell a sheep from a dog,’ said one student.
The Rabbi was not content with the answer. Another student said:
‘No, it’s when, standing some way away, you can tell an olive tree from a fig tree.’
‘No, that’s not a good definition either.’
‘Well, what’s the right answer?’ asked the students.
And the Rabbi said:
‘The light has dawned when a stranger approaches, and we can see it is our brother or sister. That is the moment when night ends and day begins.’