When the Chou tribe overthrew the last Shang king,
they had to convince the people, especially the nobles, that they had
the right to rule. The Chou told people that the gods in heaven had
told them that they were to rule. This was called "The Mandate of
Heaven", heaven's orders.
The Chou added that the gods had warned them that they
would only rule as long as they were good rulers. If they became
selfish, and thought of themselves first, before the people, that
heaven would appoint another ruling family.