Dawud bin Abi Hind said: We asked ‘Amir (Sha’bi, may Allah have mercy on him): A man left behind two sons and made a will that so-and-so should be given a share equal to one of their shares, when they are three? Sha’bi, may Allah have mercy on him, said: I instruct that he be given a quarter share. In some versions it is «أوصي بالربع» and in others «افتي بالربع », meaning he gave the fatwa of a quarter.
Hadith Referenceسنن دارمي / من كتاب الوصايا / 3285