Hazrat Umar (radhiyallahu ‘anhu) was the fortieth person to embrace Islam. At the time when he embraced Islam, Rasulullah (sallallahu ‘alaihi wasallam) and the Sahaabah (radhiyallahu ‘anhum) were in the home of Hazrat Arqam (radhiyallahu ‘anhu), and Rasulullah (sallallahu ‘alaihi wasallam) was propagating Islam in secret. Below is the incident of how Hazrat Umar (radhiyallahu ‘anhu) embraced Islam:
One day, the Quraish held a meeting in which they (called for a volunteer and) said, “Is there anyone here who will kill Muhammed (sallallahu ‘alaihi wasallam)?” Hazrat Umar (radhiyallahu ‘anhu) volunteered saying, “I will carry out this task.” At this, the people exclaimed, “Surely, you are the person who can do it, O Umar!”
With his sword hanging around his neck, Hazrat Umar (radhiyallahu ‘anhu) set out to fulfil this sinister task. However, on the way, he met Hazrat Sa’d bin Abi Waqqaas (radhiyallahu ‘anhu) of the Zuhrah clan (according to some reporters, he met another Sahaabi, not Hazrat Sa’d [radhiyallahu ‘anhu]).
On meeting Hazrat Umar (radhiyallahu ‘anhu), Hazrat Sa’d (radhiyallahu ‘anhu) asked him, “O Umar, where are you going?” Hazrat Umar (radhiyallahu ‘anhu) replied, “I am going to kill Muhammed (sallallahu ‘alaihi wasallam – may Allah forbid!).”
Hazrat Sa’d (radhiyallahu ‘anhu) then said, “Don’t you see that Banu Haashim, Banu Zuhrah and Banu Abde Munaf clans will kill you in revenge?”
Hearing this response, Hazrat Umar became upset and said, “It seems that you also have renounced the religion of your forefathers (and become a Muslim)! Let me kill you first!”
Saying this, Hazrat Umar (radhiyallahu ‘anhu) drew out his sword. Hazrat Sa’d (radhiyallahu ‘anhu) declared, “Yes, I have become a Muslim!”, and saying this, he also drew out his sword. They were about to commence fighting when Hazrat Sa’d (radhiyallahu ‘anhu) said, “You should first set your own house in order. Your sister and brother-in-law have both accepted Islam.”
Hearing this, Hazrat Umar (radhiyallahu ‘anhu) became extremely angry and immediately went straight to his sister’s house. The door of the house was locked from inside, and both husband and wife were learning the Qur’aan from Hazrat Khabbaab (radhiyallahu ‘anhu)
Hazrat Umar (radhiyallahu ‘anhu) knocked at the door and shouted for his sister to open it. Hearing the voice of Hazrat Umar (radhiyallahu ‘anhu), Hazrat Khabbaab (radhiyallahu ‘anhu) hid himself in some inner portion of the home, and in his haste, he forgot to take the pages of the Qur’aan Majeed with him.
When his sister opened the door, Hazrat Umar (radhiyallahu ‘anhu) struck her on the head, causing her head to bleed, and then addressed her saying, “O enemy of yourself! Have you also forsaken your religion!?” Hazrat Umar (radhiyallahu ‘anhu) then went inside and asked, “What were you doing, and who was the stranger I heard from outside?” His brother-in-law replied, “We were talking to each other.”
Hazrat Umar (radhiyallahu ‘anhu) said to him, “Have you also left your religion and embraced the new religion?” His brother-in-law replied, “But what if the new religion is the true religion?” Hearing this, Hazrat Umar (radhiyallahu ‘anhu) pulled his brother-in-law by his beard and attacked him, dropping him to the ground and beating him most severely.
When his sister intervened, trying to save her husband, he slapped her so violently that her face began to bleed. Since she was, after all, Hazrat Umar’s (radhiyallahu ‘anhu) sister, she openly exclaimed, “Umar! We are only being beaten because we have become Muslims! Definitely, we have become Muslims, so now do whatever you want to do with us!”
Thereafter, Hazrat Umar’s (radhiyallahu ‘anhu) eyes fell on the pages of the Qur’aan Majeed which had been left behind by Hazrat Khabbaab (radhiyallahu ‘anhu). By this time, Hazrat Umar’s (radhiyallahu ‘anhu) anger had subsided, and he felt a bit ashamed over his sister’s bleeding.
Seeing the pages of the Qur’aan Majeed, he said, “Very well, show me, what are these pages?” His sister replied, “No, you are unclean, and no unclean person can touch these pages.” Hazrat Umar (radhiyallahu ‘anhu) insisted, but his sister was not prepared to allow him to touch the pages unless he made wudhu and ghusl.
Eventually, Hazrat Umar (radhiyallahu ‘anhu) took a bath, and then took the pages and began to recite. The pages had the verses of Surah Taha written upon them, and he commenced reciting from the beginning of the surah. When Hazrat Umar (radhiyallahu ‘anhu) reached the following verse, his entire condition had changed and he was a different man altogether:
إِنَّنِي أَنَا اللَّهُ لَا إِلَٰهَ إِلَّا أَنَا فَاعْبُدْنِي وَأَقِمِ الصَّلَاةَ لِذِكْرِي ﴿١٤﴾
Indeed, I am Allah. There is none worthy of worship besides Me, so worship Me, and establish salaah for My remembrance. (Surah Taha v. 14)
Hazrat Umar (radhiyallahu ‘anhu) then said, “Alright, take me to Muhammed (sallallahu ‘alaihi wasallam).” Hearing this, Hazrat Khabbaab (radhiyallahu ‘anhu) came out from hiding and said, “O Umar! Glad tidings for you! Last night, which was Thursday night, Rasulullah (sallallahu ‘alaihi wasallam) made dua saying, ‘O Allah! Strengthen Islam with either Umar or Abu Jahl, whomsoever You like (as these two people were renowned for their strength and power).’ It seems that the dua of Rasulullah (sallallahu ‘alaihi wasallam) has been answered in your favour.”
Hazrat Umar (radhiyallahu ‘anhu) then went to Rasulullah (sallallahu ‘alaihi wasallam) and embraced Islam on Friday morning.
Hazrat Umar’s (radhiyallahu ‘anhu) accepting Islam was a terrible blow to the morale of the disbelievers, but the Muslims were still few in number, and not just the city of Makkah – but the entire country of Arabia was against them. Hence, the disbelievers intensified their efforts, held meetings and held discussions for the purpose of trying to completely annihilate the Muslims, and adopted different methods to oppose Islam.
Nevertheless, with Hazrat Umar (radhiyallahu ‘anhu) now on their side, the Muslims started performing their salaah openly in the Haram.
Hazrat Abdullah bin Mas’ood (radhiyallahu ‘anhu) says, “Hazrat Umar’s (radhiyallahu ‘anhu) accepting Islam was a great victory for the Muslims, his emigration to Madinah was a great help for the Muslims, and his becoming the Khalifah was a great blessing for the Muslims.”
(Fazaa’il-e-A’maal [English] pg.28-31, [Urdu] pg. 22-23)