بسم الله الرحمن الرحيم
When Ignorance is an Excuse

"Someone who is able to learn and simply neglects to do so is accountable for the ignorance that he has on account of his negligence."
  
Ignorance, as a term, can be defined as a person being devoid of knowledge. More precisely, it is to be lacking knowledge that one is supposed to be acquainted with. People, naturally, start out life in a state of ignorance. In fact, at the beginning of any pursuit, the person will be in a state of ignorance concerning it and will have to do what is necessary to dispel that ignorance.  
           
And Allāh brings you fourth from the wombs of your mothers knowing nothing.  (Soorah al-Nahl: 78)      
              
Once a man gave to the Prophet (peace be upon him) a flask of wine as a gift. The Prophet (peace be upon him) asked the man: "Do you know that Allāh has prohibited this?" The man replied that he did not know of its prohibition (Sahîh Muslim, 1579).  The man had not yet come to know that wine had been prohibited, so he was not blamed or rebuked. This hadîth shows us that a person who really does not know something is exempted from sin.    
 
And Allāh would not punish a people until after He had sent to them a Messenger. (Soorah al-Isrâ': 15)  
    
And this is the case for someone who has truly not received knowledge. Someone who is able to learn and simply neglects to do so is accountable for the ignorance that he has on account of his negligence. This is stated as a general axiom of Islamic Law: "A legally accountable person can not use ignorance as a defense if he had been able to overcome his ignorance."
This is because Allāh has sent his Messengers to us and has required all of us to learn the Message and then to act upon it. Allāh obligates us to know what is required of us and to act accordingly. 
 
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