Ata and Ikrimah (may Allah have mercy on them) said: "Whoever makes a bequest of a share in his wealth, it is nothing, because he has not specified." And Hasan al-Basri (may Allah have mercy on him) said: "His right in every case is one-sixth."
Hadith Referenceسنن سعید بن منصور / كتاب ولاية العصبة / 1540
Hadith Takhrij«أخرجه سعيد بن منصور فى «سننه» ترقيم الدرالسلفية برقم:، 363، وابن أبى شيبة فى «مصنفه» برقم: 31443، 31444»