《周礼·地官司徒·师氏&媒氏》
凡一年的四季有自然灾害而使民困病，就拿着旌节巡视国都中以及郊野，而用王的名义对灾民施行救济。
凡岁时有天患民病，则以节巡国中及郊野，而以王命施惠。
For any natural calamities in the four seasons of a year, which cause troubles and illnesses among people, he shall hold the flag as a symbol of authority and go around the national capital and the outskirts, and provide relief to the people in the name of the king.