Masruq (may Allah have mercy on him) said: "A man was making a will and began to bequeath things that were not appropriate, so indeed Allah has made the best division among you, and whoever leaves Allah's division and follows his own opinion goes astray. You should make a will for those who are not your heirs, then leave the wealth according to Allah's division."
Hadith Referenceسنن سعید بن منصور / كتاب ولاية العصبة / 1538
Hadith Takhrij«أخرجه سعيد بن منصور فى «سننه» ترقيم الدرالسلفية برقم: 360، 361، 362،، 585، والبيهقي فى«سننه الكبير» برقم: 12708، وابن أبى شيبة فى «مصنفه» برقم: 31646»