He was the second of the great Khulafa of the Messenger of Allaah (sallAllahu ‘alayhi wa sallam), Abu Hafs, ‘Umar bin al-Khattab bin Nufail (radhiAllahu ‘anhu). He died in the year 23 A.H. after leading the Fajr prayer, he was stabbed whilst leading the prayer. His Khilaafah lasted for 10 years after the Khilaafah of Abu Bakr as-Siddeeq (radhiAllahu ‘anhu‏), the Messenger of Allaah (sallAllahu ‘alayhi wa sallam) was always seen with Abu Bakr & Umar (radhiAllahu ‘anhum).

The Messenger of Allaah (sallAllahu ‘alayhi wa sallam) said:

"Verily Allaah has placed the truth upon the tongue & heart of Umar."

[Narrated by Ibn Umar & Abu Dharr, collected by Ahmad, Tirmidhee, Abu Dawood & authenticated by al-Albaanee in ‘Saheeh al-Jaami’ ]

Talha bin Ubaidullaah (radhiAllahu ‘anhu) said:

"That Umar was not the first to embrace Islaam nor the first to make Hijraa but was the foremost in Zuhud & desiring for the hereafter out of us."

The Messenger of Allaah (sallAllahu ‘alayhi wa sallam) mentions as is narrated in Saheeh al-Bukharee by Jabir bin Abdullaah (radhiAllahu ‘anhu):

"I saw myself entering Paradise, and behold! I saw ar-Rumaisa the wife of Abu Talha. And I heard footsteps, so I asked who is that? It was said: It is Bilal. Then I saw a palace with a lady sitting in its courtyard. So I said whose is this? They said it is Umar’s. I wanted to enter it and see it then I remembered your Ghira (possessive jealousy)."

Then ‘Umar said: “Let my parents be sacrificed for you O Allaah’s Messenger how dare I think of my Ghira being offended by you?”

The Messenger of Allaah (sallAllahu ‘alayhi wa sallam) said:

"If there were to be a Prophet after me it would have been Umar al-Khattab."

[Narrated by Uqbah bin Aamir, & collected by Ahmad, Tirmidhee & Hakim, & made Hasan by al-Albaanee in Saheehah (327)]

He is 'Umar ibn Al Khattab ibn Nufayl ibn 'Abdul Uzzah. He became Muslim in the sixth year of prophethood when he was twenty seven years of age. He was one the ten Companions given glad tidings of Paradise.

His acceptance fo Islaam was brought about by the du'a of the Prophet (ﷺ), Ibn 'Umar (radiAllaahu 'anhu) narrated that Allah's Messenger said 

"O Allaah, help Islaam with one of the two men that is most beloved to you: Abu Jahl or with 'Umar ibn Al Khattab. And the most beloved of the two to him was 'Umar."

He was also the first person to publicly proclaim Islaam. Ibn Abbas said:

"The first person to publicly proclaim Islaam was 'Umar ibn Al Khattab. Allah has placed truth upon' Umar's tongue and heart."

Uqbah ibn Amir , narrated that the Prophet (ﷺ) said:

"Were there to be a prophet after me, it would have been 'Umar."

And from Abu Sa'eed, who said, "Allah's Messenger (ﷺ) said:

'The angels speak on his tongue.'

Aisha (radiAllaahu 'anha) narrated that the Prophet (ﷺ) said:

"There had been among the people before you inspired persons and if there were any such among my Ummar it would have been 'Umar ibn Al Khattab."

Anas also reported that the Prophet (ﷺ) said:

"(I saw in a dream that) I entered Paradise and behold, there was a palace built of gold! I asked 'For whom is this palace?' They (the angels) replied, 'For a young man of the Quriash.' The Prophet (ﷺ) added, 'I thought that was me so I asked, 'for whom?' They said, 'Umar ibn Al Khattab!'"