# The ruler who lacks understanding

"The ruler who does not understand" 

# oppressor

a person who treats people harshly and makes their lives very difficult

# the one who hates unjust gain

"the one who becomes angry when other people gain dishonestly" or "the one who hates gaining dishonestly"

# the one

This phrase can refer to the "ruler" or any person.

# prolong his days

"live longer" or "rule for a longer time"