Musannaf Ibn Abi Shaybah

It is narrated from Mughira that Hazrat Hammad said regarding the man who, at the time of his death, left behind three sons and said, "A third of my wealth is for my youngest son." Later, the eldest son said, "I do not execute such a will," and the middle son said, "I execute it." He (Hammad) said, "In my opinion, the wealth should be divided into nine parts: three parts will be given to the eldest son, and then the youngest son should be given his share and the share of the one who executed the will." Hammad says that the share should be returned to all of them, and Amir says that the one who rejected the will has only rejected it from his own share.