The Ruling on Leaving a Will and its Legal Wording

Question :

Is it obligatory to write a will? And does it require witnesses? And since I do not know the legal wording, I request that you guide me to it, and may Allah reward you with goodness.

Answer:

The will is written according to the following wording:

"I, the undersigned do hereby testify that none has the right to be worshipped except Allah, Alone without partners, and that Muhammad is His servant and His Messenger and that 'Isa is the servant of Allah and His Messenger and His Word, which He bestowed on Mary and a spirit (Ruh) created by Him, and that Paradise is true and Hell is true and that the Hour (i.e., the Day of Resurrection) will come and there is no doubt in it, and that Allah will send forth those in the graves.

I advise those whom I leave behind of my family and my descendants and all of my kin to fear Allah, the elimination of discord, obedience to Allah and His Messenger, mutual recommendation to the truth and patient perseverance upon it. And I advise them with the same advice which Ibrahim and Ya'qub, peace be upon them, gave to their sons:
"O my sons! Allah has chosen for you the (true) religion, then die not except in the faith of Islam (as Muslims)."

Then he should mention what he must leave from one third of his wealth or less than that, or a specific amount which is not more than a third and he should make his legal obligations clear,

and mention the trustee of that. A will is not obligatory, but it is highly recommended if one wishes to bequeath anything, according to what has been confirmed in the Two Sahihs, on the authority of Ibn 'Umar - may Allah be pleased with him - from the Prophet that he said:
"It is not right for a Muslim man who has anything he wants to bequeath to stay anywhere for two nights unless he has a will with him."

However, if he has debts or rights which he must pay for which there are no written records to confirm for their recipients, he must testify to them, so that the rights of the people are not lost. He must then call two just witnesses to his will and it should be attested by someone whom he trusts among the scholars, so that it may be depended upon, and he should not suffice himself with his written hand only, because it may be unclear to the authorities, and it might not be easy for those among the reliable people whom he knows (to understand it). And Allah is the Granter of success.

Source:
Fatawa Islamiyah, Vol. 5 Pages 58-59