The Prophet said, “If there were to be a prophet after me, indeed he would be ‘Umar, son of Khattab.” [Sunan Tirmidhi: 3686]
History does not produce men like ‘Umar often. He was a person from whom truth flowed naturally; a man of intuition, he was on his way to kill the Prophet (peace be upon him) and ended up accepting Islam! His love for Allah and his deen was so great, while all the other Muslims were hiding their Islam, he was ready to proclaim it. The Prophet (peace be upon him) called him, Al-Farooq, the one who clearly distinguishes the truth from falsehood.
Satan had given up on ‘Umar (radhiAllahu anhu). The Prophet said, “O son of Khattab, by the one in whose hand is my soul, whenever Satan sees you taking a path, then he will take another path.” [Sahih Bukhari: 5735]
When the enemies of Allah would hear about ‘Umar (radhiAllahu anhu), their knees would weaken and their hearts would tremble.
One of the key qualities of ‘Umar ibn al Khattab which exemplified his character was social justice. For him, social justice meant redistribution of power and income in such a way that, when introduced at the lowest level, it spreads upward to all the reaches of society. He established the pillars of justice, Al Adl, The first social policy infrastructure is found in all of history to be set up by ‘Umar (radhiAllahu anhu). The concept of Bait ul maal was established by him (radhiAllahu anhu). He would roam the streets of medina at night to help his people. The foundation of child benefit or children allowance, meaning every child gets benefit every week to keep them afloat, followed by the west today was initially set by him.
One night ‘Umar went on his rounds as usual when he heard the voice of a baby crying. ‘Umar stood outside the house for some time, but when the baby did not stop crying he knocked at the door and was admitted inside the house. He saw that a woman held a small baby in her lap and the baby continued to cry. ‘Umar turned to the lady and said, “What sort of mother are you? The baby is crying, and you do not feed it with your milk!”
The woman said, “Go and ask ‘Umar as to what sort of Caliph he is! He has ordained that a child would not get a stipend until it was weaned. In order to secure the stipend for our child we are trying to wean it.”
‘Umar (radhiAllahu anhu) told the woman “Feed your baby with your milk, and rest assured you will get the stipend for your baby even though it is not weaned.”
The following day in Fajr Salah, ‘Umar cried so much that the Sahaba said we could not understand what he was reciting and after he had finished he passed orders that stipends would be allowed for children from their date of birth.
People came from faraway lands to seek the justice of ‘Umar (radhiAllahu anhu). Ibn Abd Al-Hakim reported: Anas, May Allah be pleased with him, said that a man from the people of Egypt came to ‘Umar ibn Al-Khattab and said, “O leader of the believers, I seek refuge in you from injustice!” ‘Umar replied, “You have sought someone willing.” The man said, “I competed with the son of Amr ibn Al-‘As and I won, but he started striking me with a whip and saying: I am the son of the dignified!” Upon this, ‘Umar wrote to Amr ordering him to travel to him with his son. 
He came with his son and ‘Umar said, “Where is the Egyptian?” He gave him the whip and told him to strike the son of Amr. The man started striking him while ‘Umar was saying, “Strike the son of the illiterates!” Anas said, “By Allah, the man struck him and we loved his striking, and he did not stop until we wished he stopped.” Then ‘Umar said to the Egyptian, “Direct it to Amr.” The Egyptian said, “O leader of the believers, it was only his son who struck me and I have settled the score.” ‘Umar said to Amr, “Since when did you enslave the people though they were born from their mothers in freedom?” Amr said, “O leader of the believers, I did not know about this and he did not tell me.” (Ibn Abdil Hakam,Futuh Masr 290)
In 637 CE, Jerusalem offered a truce, provided that the Khalifa come himself from Medina to sign the treaty. ‘Umar (radhiAllahu anhu) set out for Jerusalem with a slave and a camel. No retinue accompanied the Caliph. The slave and he would take turns riding the camel and they also gave the camel time off from carrying either passenger. When they approached Jerusalem, ‘Umar (radhiAllahu anhu) was walking and had to cross through muddy ground, as a result of which his feet and clothes got mud on them. When ‘Umar (radhiAllahu anhu) entered Jerusalem, he was holding the rope of his camel leading it and his clothes were patched and muddy.
Abu Ubaidah (radhiAllahu anhu), the commander in chief of the Muslim army and himself a very pious man, suggested that he change his clothes so that the people of Jerusalem, accustomed to the pomp and grandeur of kings and emperors, were not dissuaded from handing the keys of Jerusalem over to him. ‘Umar (radhiAllahu anhu) hit him hard on the chest and reminded him that they had been a disgraced nation. What had brought them honour and elevated them was Islam; should they seek honor from anything else, they would surely be humiliated again.
“The only way for success is the way of the Holy Prophet” he said.
When the people of Jerusalem saw ‘Umar’s simplicity they started crying. Such was his sense of justice, He would sleep beneath a tree peacefully unguarded and it was only this quality which enabled him to do so.
In the year of Ar ramadah 18th year after hijrah, the year the Muslims were hit by famine, 60,000 refugees came to Medina and ‘Umar (radhiAllahu anhu) would himself carry oil and food to the people and whenever he would see that the people were deprived of something he would deprive himself of that as well, if they didn’t have meat he would deprive himself from meat if they didn’t have oil he would deprive himself from oil to the extent that the Sahaba feared he would die. He would say, “How can I be a shepherd when I am not struck with what my flock is struck with.”
Even before his death at the hands of the man Abu lulu al majoosi, he said some words to ‘Umar (radhiAllahu anhu) from which the caliph understood that he meant to kill him but he did not take action because it was against his sense of justice to punish a man just for his words.
Imam Ahmad Ibn Hanbal records a hadith narrated upon the authority of Sayyiduna Qabisah ibn Jaabir who said:
“I haven’t seen anyone more knowledgeable about the book of Allah and His religion, nor anyone more upholding of the limits imposed by Allah, nor anyone more feared and respected in the breasts of men than ‘Umar ibn Al-Khattaab.” [Fadail al-Sahaba, Vol. 1, Page 330, Hadith 472]
He was a just leader unparalleled by any other from the time he accepted Islam to his death.  He was Al-Farooq.