Wise teacher: "How can we determine the hour of dawn, when the night ends and the day begins?"
"When from a distance you can distinguish between a dog and a sheep?" suggested one of the students.
"No," was the answer of the teacher.
"Is it when one can distinguish between a figtree and a grapevine?" asked a second student.
"Please tell us the answer then," said the students.
"It is," said the wise teacher, "when you can look into the face of a human being and you have enough light to recognize in him your brother. Up until then it is night and darkness is still with us."
-- An old wise tale