"Disease" - in the spiritual sense - is all kinds of sinful delusion, unrighteousness, false worldview, false beliefs of man.

"Disease" spiritual is the consequence of man's violation, perversion of God's Will, His Commandments, Covenants, Laws.

"Sickness of the Eyes," i.e., when a person "cannot see," i.e., does not perceive the Councils of God's Word Covenants.   

"Sickness of the Heart," i.e., when a person's senses are closed to accepting and doing the Will of God, His Commandments.    

"Diseases of the Feet," i.e., when a person does not consciously "walk," does not strive to fulfill God's Laws.   

"Diseases" spiritual "inborn" are diseases inherited from parents, relatives, who have been affected by false beliefs, delusions, sins, which they have inherited from their children.   

 "Diseases" spiritual "acquired" are spiritual diseases that have changed a person's thinking and way of life by his own desire, assumption, choice, or by virtue of a person's being (voluntarily or involuntarily) in a certain "spiritually contagious", unholy, sinful upbringing environment.  

 "The disease of supposed righteousness" is a person's unjustifiably high conceit of his own righteousness. (This spiritual sickness is often expressed in the official names of religious faiths, which thus emphasize their difference from others.)        

  "Sick" is a symbolic image of a person whose thinking is affected by a sinful ideology, a false worldview, a belief, and who as a consequence is unable, unwilling to lead a righteous life.