Maat is the Goddess of Truth and Justice who personifies cosmic order and harmony as established by the Creator God at the beginning of time. Her symbol is an ostrich feather. Judges were regarded as priests of Maat. In the hall of judgement at the weighing of the heart, the heart of the deceased was placed on the scales of justice, balanced against the feather of Maat, symbol of justice.
Since Horus was said to be the sky, he was considered to also contain the sun and moon. It became said that the sun was his right eye and the moon his left, and that they traversed the sky when he, a falcon, flew across it.