From the house of his sister, Umar proceeded to the house of Arqam at the foot of the Safa hill, where the Holy Prophet was lodged.
Umar knocked at the door of the house of Arqam.
"Who comes", enquired the guard.
"Umar bin al-Khattab". said Umar.
As the guard peeped through the door he saw that Umar had buckled his sword. The guard therefore hesitated to open the door.
Hamza said to the guard, "Open the door; if he comes in peace he will be welcome. If he is bent on mischief, we are enough to overpower him".
Umar was admitted. Hamza caught him by the hem of his cloak and said, "Umar, what brings you here?" The Muslims with drawn swords surrounded Umar, so that he could be overpowered if he showed any signs of violence.
Hearing the noise, the Holy Prophet came out of his cell. Addressing Hamza the Holy Prophet said, "Leave him Let him come forward".
As Umar stepped forward the Holy Prophet said Umar, how long will you stray from the path of Islam. Has the time not come for you to see the truth?"
Umar said, "Verily the time has come for me to see the truth. I have come to profess my faith in Islam".
The Holy Prophet stretched his hand. Umar held the hand with reverence and said, "I declare that there is no god but Allah, and that Muhammad is the Messenger of God".
In joy the Muslims shouted "Allah-o-Akbar". The Holy Prophet embraced Umar. The other Muslims embraced Umar one by one. Umar was the fortieth person to become a Muslim.
That day even Gabriel congratulated the Holy Prophet on the conversion of Umar. Gabriel said: "O Prophet of God, the dwellers in Heaven rejoice at the conversion of Umar and offer you their congratulations". Intoxicated with the joy of having become a Muslim, Umar proceeded to various parts of Mecca to announce that he had become a Muslim. He first went to the house of his maternal uncle Abu Jahl. He knocked at the door of the house of Abu Jahl.
"Who comes", asked Abu Jahl.
"It's Umar", said Umar. Abu Jahl opened the door and said,
"Welcome nephew". Umar said,
"Uncle do you know, I have become a Muslim." Abu Jahl said,
"Do not talk like that. I know that a man of your views can never become a Muslim". Umar said,
"No, uncle it is a fact that I have become a Muslim." Abu Jahl thereupon said,
"If what you say is true then be damned". Saying this Abu Jahl shut the door in the face of Umar.
Thereafter Umar went to see some other Quraish chiefs. He told them of his conversion to Islam. Like Abu Jahl they damned him and shut the doors of their houses against him.
Then Umar proceeded to the Ka'bah. There he saw Jamil bin Ma'mar al-Jamahi who enjoyed reputation for spreading reports in Mecca. Umar told him that he had accepted Islam. Jamil rose from his feet, and cried at the top of his voice:
"O ye Quraish, know that Umar bin al Khattab has been converted to Islam, and apostatised from the faith of his forefathers. "
On hearing this some Quraish youth gathered at the Ka'bah. Umar said,
"What Jamil said is not correct. I have not apostatised: I have seen the truth and accepted Islam". Thereupon the Quraish youth rushed at Umar with a view to beating him. A Shaikh dressed in Yemeni robes Al-Aas bin Wail passed that way, and enquired what was the matter. The Quraish said that Umar had apostatised, and they wanted to punish him for straying from the faith of his forefathers. The Shaikh said,
"A man should be free to choose whatever religion he iikes. Why beat him for that?" Abu Jahl also happened to come that way. Seeing the Quraish, he said,
"I offer protection to my nephew". Umar said,
"Uncle, I do not need your protection. For me the protection of God and the Holy Prophet is enough".
Then Umar went to the Holy Prophet and told him that he had publicly announced his conversion. Heretofore those who were converted to Islam kept their conversion to Islam secret for fear of the oppression of the Quraish. They also prayed in secret. Umar submitted to the Holy Prophet:
"O Messenger of God are we not in the truth?". The Holy Prophet said,
"Why not, we are verily in the truth".
"Then why should we not pray in the public? Has not the time come for us to declare our faith publicly?" said Umar. Umar tried to prevail on the Holy Prophet that the truth of Islam should become manifest. The Holy Prophet agreed with Umar.
The following day all the Muslims emerged from the house of Arqam and proceeded to the Holy Ka'bah, in two lines, one led by Umar, and the other by Hamza. At the Ka'bah the Muslims prayed openly. The Quraish watched the Muslims pray and said, "Verily by the conversion of Umar to Islam, the Muslims have taken the revenge from the Quraish".
After the Muslims had prayed in the Ka'bah, the Holy Prophet conferred on Umar the title of "Al-Faruq," for on that day through the efforts of Umar, the truth of Islam had become manifest.