Muwatta 2226

He said: I also heard Malik say of a sick man who makes a bequest, and asks his heirs for permission for his bequest, while he is ill and has only a third of his property, and they permit him to bequeath more than a third to some of his heirs: they may not retract that. If that were allowed to them, every heir would do that, and when the testator died they would take that for themselves and prevent the bequest in his third, and what he was permitted in his property. ¹

Belongs to the Muwatta, Book of Bequests. Source: the Muwatta. Mentions Malik ibn Anas. Built on in the chapters on bequest (wasiyya).