He said he would dictate something for his followers' benefit...
He said he would dictate something for his followers' benefit, assuring them that if they adhered to it, they would never go astray. Some of the people present thought that since the Prophet - May God's peace and blessings be upon him - was severely ill and since the Muslims already had the Quran, no further writing was necessary. It is related that that thought belonged to Umar.
The people present disagreed among themselves, some wishing to bring writing materials and take down what the Prophet would dictate, and others thinking that any further writing besides that of the Book of God would be superfluous.
Muhammad asked them to leave, saying, ‘You must not disagree in my presence.' Ibn Abbas feared that Muslims might lose something important if they did not bring the writing materials but Umar held firmly to his decision which he based upon God's Own words in His Book: “In this scripture, We have left out nothing.” (The Life of Muhammad, Cairo, 1935) In an article captioned Iqbal and Islamic Polity, published in the April 1964 issue of the monthly magazine, Muslim News International , of Karachi, Pakistan, the writer**,** Jamilud-Din Ahmad, says: “...The question which confronts the Muslim countries is, whether the law of Islam is capable of evolution - a question which will require great intellectual effort and is sure to be answered in the affirmative; provided the world of Islam approaches it in the spirit of Umar - the first critical and independent mind in Islam, who, at the last moments of the Prophet, had the moral courage to utter these remarkable words: 'The Book of God is sufficient for us.'“ The writer quoted above apparently is very proud of the “moral courage” of Umar.
Muhammad, the Messenger of God, was on his deathbed, and perhaps did not have many hours to live. It was this time that Umar chose to demonstrate his moral courage. At Hudaybiyya, Muhammad Mustafa had ordered him to carry a message to the Quraysh in Makkah but he refused to go on the plea that since there was no one in that city to protect him, they would kill him.