Being Islamically accountable (mukallaf), means that the person is accountable for his/her deeds in the Hereafter. A person is considered Islamically accountable (mukallaf), when three conditions are met: The person is pubescent, sane and has received the basic call of Islam. The accountable person is obligated to embrace Islam and comply with the rules that are obligatory upon them. The scholars of Islam defined what makes a person pubescent:

Puberty for a male is reached when one of two things occur:

• When his semen (maniyy) is discharged or
• When he becomes 15 lunar years old

Puberty for a female is reached when one of three things occur:

• When her semen (maniyy) is discharged, or
• When she menstruates, or
• When she becomes 15 lunar years old

As such, there are three (3) types of people who are not accountable for their deeds in the Hereafter: 

• The child who died before becoming pubescent 
• The person whose insanity occurred before pubescence, then remained throughout puberty until his death  
• and the pubescent, sane individual who never received the call of Islam, i.e., the Testification of Faith that “No one is God except Allah and that Muhammad is the messenger of Allah.”

Allah said in Surat al Isra’ verse # 15:

﴿ وما كنا معذبين حتى نبعث رسولاً ﴾ سورة الإسراء

The verse means: [Allah will not punish in the Hereafter those who do not receive the basic message (of Islam) unless He reveals a prophet].

The Prophet, salla-l-lahu ^alayhi wa sallam, said:

“رفع القلم عن ثلاث: عن النائم حتى يستيقظ وعن الصبي حتى يحتلم وعن المجنون حتى يعقل” رواه الإمام أحمد

This hadith means: “The Pen has been lifted from writing the deeds of three: the one who is asleep until he wakes up, the child until he becomes pubescent, and the insane person until he becomes sane,” narrated by Imam Ahmad.