“I would like the people to reduce (the will) from one third to one quarter, because the Messenger of Allah (ﷺ) said: 'One third is a lot.'”
Sunan Ibn Majah Book 22, Hadith 17
← Previous Hadith “(Allah says) O son of Adam! I have given you two things which you do not deserve (except by mercy of Allah (SWT)): I allow you to dispose of a share of your wealth when you are on your deathbed, in order to cleanse and purify you, and my slaves pray for you after your life is over.”

Sunan Ibn Majah Book 22, Hadith 16 Next Hadith → “The Prophet (ﷺ) addressed them when he was on his camel. His camel was chewing its cud and its saliva was dripping between my shoulders. He said: 'Allah (SWT) has allocated for each heir his share of the inheritance, so it is not permissible (to make) a bequest for an heir. The child belong to the bed and the adulterer gets the stone. Whoever claims to belong to someone other than his father, or (a freed slave) who claims that his Wala is for other than his Mavali, upon him will be the curse of Allah, the angels and all the people, and no charge nor equitable exchange will be accepted from him.” Or he said: “No equitable exchange nor change.”

Sunan Ibn Majah Book 22, Hadith 18