قَالَ رَسُولُ اللَّهِ ص رُفِعَ الْقَلَمُ عَنْ ثَلَاثَةٍ عَنِ النَّائِمِ حَتَّى يَسْتَيْقِظَ وَ عَنِ الْمَجْنُونِ حَتَّى يُفِيقَ وَ
عَنِ الطِّفْلِ حَتَّى يَحْتَلِمَ
The Prophet (peace be upon him) said: The pen of responsibility has been lifted from three groups: from sleepers until they wake up, from the insane until they are recovered and from children until they reach puberty.
As long as you have not reached the age at which you become duty bound(Bulugh)1, you are not obliged to make up for what you have done wrong.
However, rights related to people have to be compensated. The point is that as long as you have not reached the age of Bulugh, your parents are to be held accountable. but if you have become duty bound you are the responsible of making up for the damages you did to others' properties.
Therefore, you have to gain the satisfaction of the person from whom you have stolen a book by giving back the book if possible or another edition of the book if possible or the price of the book as the last resort.
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