Sayyiduna Zaid bin Thabit (may Allah be pleased with him) was the first person who gave the verdict of «عَول» (reduction) in inheritance, and the maximum «عَول» reached up to two-thirds.

A case was brought before Sayyiduna Ali (may Allah be pleased with him) regarding a man who had left behind parents, two daughters, and a wife. He said to the wife: "I see that your one-eighth share has become one-ninth."

Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: "There is no «عَول» in inheritance."

Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: "Do you think that the one who counted the grains of sand in Al-'Alij would assign half, a third, and a quarter in wealth? Inheritance is only divided into two halves, three thirds, and four quarters."

I said to Sayyiduna Ibn Abbas (may Allah be pleased with them): "People neither accept my words nor yours. If I and you die, they will not divide the inheritance according to what we have said." He said: "Then come, let us place our hands on the Ka'bah and invoke a curse, that whoever is lying, may Allah's curse be upon him, because Allah has decided according to what we have said."