Disproof of Fatherhood in Retaliation and Studying its Extension to Ancestor

One of the conditions in executing retaliation that all the great jurists agree on is disproof of fatherhood. Apart from the philosophy of legislation of this decree in Islam, disproof of retaliation of a father who committed a deliberate crime on his own child, only by the virtue of the in fallible traditions is fixed; but with regard to this point that non - execution of father's retaliation is against rule and decree of retaliation and in such instances the method of jurists is only to be satisfied with the same cases in that proving reasons are stipulated and in the traditions on joining grandfather to father which jurists take them into consideration are not expressed explicitly, so in this matter the view of joining grandfather to father which is applied generally by the virtue of traditions is objected.