How does king's appeal to eternal and natural law help him examine human laws?

By appealing to eternal and natural law, the king can evaluate human laws against these higher moral standards. This allows him to determine whether human laws are just and in alignment with universal moral principles, or if they are unjust and need to be reformed in order to better serve their purpose. Ultimately, this helps the king ensure that the laws of the land are ethical and promote the well-being of society.