The Advice Umar (Radhiallahu ‘Anhu) gave to Someone:
Umar (Radhiallahu ‘Anhu) once advised a man saying, "Never allow people to distract you from yourself because you are ultimately responsible for yourself and not for them. Never spend your days wandering about because everything you do is recorded. Always carry out a good deed whenever you sin because I have never seen anything catch up with another as fast as a newly done good deed catches up with an old sin."  Umar (Radhiallahu ‘Anhu) also said, "Stay away from that which causes you harm, ensure that you have righteous friends even though such people are scarce and consult those who fear Allah about all your matters.” 
Eighteen Wise Advices from the Lips of Umar (Radhiallahu ‘Anhu):
Sa'eed bin Musayyib reports that there were eighteen guidelines that Umar (Radhiallahu ‘Anhu) formulated for the people, every one of which is replete with wisdom. He said:
"(1) When someone disobeys Allah in matter that impacts on you, you can give him no punishment worse than obeying Allah in matters that impact on him.
(2) Always assume the best about your brother unless you learn something about him that you absolutely cannot reconcile.
(3) Never assume the worst about any statement that a Muslim makes as long as you are able to make a favorable interpretation.
(4) The person who exposes himself to slander must never rebuke anyone who holds a bad opinion of him.
(5) Whoever guards his secrets will retain the choice in his hands.
(6) Ensure that you keep true friends to stay under their wings because they are a source of beauty during times of prosperity and a means of protection during times of hardship.
(7) Always speak the truth even though it leads to your death.
(8) Never delve into matters that do not concern you.
(9) Do not ask about matters that have not occurred because that which has already taken place is enough to preoccupy you from that which has riot.
(10) Never seek your needs from one who does not want to see your success.
(11) Never treat false oaths lightly because Allah will then destroy you.
(12) Never keep the company of the sinners to learn from their sinful ways.
(13) Keep away from your enemy.
(14) Beware even of your friends, except for the trustworthy one and none can be trustworthy unless he fears Allah.
(15) Be humble when in the graveyard,
(16) Submit to Allah's obedience and
(17) Seek Allah's protection at the time of disobeying His commands.
(18) Consult with those who fear Allah because Allah says:
“From Allah's bondsmen, it is only those with knowledge (those who
recognjse Hjm) who fear Him.” [Surah Faatir, verse 28] 
Muhammad bin Shihaab reports that Umar bin Khattaab (Radhiallahu ‘Anhu) said, "Never delve into matters that do not concern you, keep your distance from your enemy and be cautious even of your friends unless he is a trustworthy person because nothing can compare with a trustworthy person. Never keep the company of a sinner because he will teach you his sinful ways and never disclose your secrets to him. Always consult with those who fear Allah." 
"Men are of three Categories and Women are of three Categories"
Samurah bin Jundub (Radhiallahu ‘Anhu) reports that Umar (Radhiallahu ‘Anhu) once said, "Men are of three categories and women are also of three categories. As for women, there is the woman who is chaste, is a Muslim, is gentle, loving and has many children. She assists her family against the (fashions and influences of the) times and does good to assist in the times against her family. It is however rare to find such a woman. The second is the woman makes many demands and does nothing more than bear children. The third is a parasitic yoke that Allah places around the neck of whoever He pleases and removes from the neck of whoever He pleases.
As for the three categories of men, one is the man who is chaste, easy-going, gentle, holding intelligent opinions and always offering the best counsel. Whenever any matter arises, he consults with others and matters are always settled with his opinion. The other is the man who has no sound opinions but when any matter arises, he consults men of good judgement and does what they advise. The third man is the bewildered person who cannot distinguish right from wrong. He neither consults with others nor takes the opinion of someone offering guidance." 
His Advice to Ahnaf bin Qais:
Ahnaf bin Qais narrates that Umar(Radhiallahu ‘Anhu) once said to him, "O Ahnaf! The person who laughs too much loses respect and the one who jokes too much is not taken seriously. The one, who talks too much, makes too many mistakes, the one who makes too many mistakes loses modesty, the one who loses modesty loses piety and the heart of the one who loses piety eventually dies." 
Another narration states that Umar (Radhiallahu ‘Anhu) said. "The person who laughs too much loses respect, the one who jokes too much is not taken seriously and the one who indulges too much in something is known for it. The one who talks too much, makes too many mistakes ..." The rest of the narration is like the one above.
"There are some servants of Allah who annihilate falsehood by staying away from it and revive the truth by speaking of it"
Umar (Radhiallahu ‘Anhu) said, "There are some servants of Allah who annihilate falsehood by staying away from it and revive the truth by speaking of it. When given encouragement (to do good), they are encouraged and when warned against something, they take heed. When fearing something, they are never off guard. With the power of conviction, they are able to see things they have never seen, blending these into those memories that never leave. Their fear for Allah has purified their souls and they forsake that which will leave them (the pleasures of this world) for that which will always remain theirs (the bounties of the Aakhirah). Life is a bounty for them and death is a source of honour because they will marry the wide-eyed damsels of Jannah and be waited upon by servants of eternal youth." 
Miscellaneous Advices that he Gave:
Umar (Radhiallahu ‘Anhu) once said, "Become coffers of the Qur'aan, fountains of knowledge and ask Allah for your sustenance on a day-to-day basis." Another narration states that he also added, "Remain in the company of those who repent excessively because such people have the softest hearts." 
Umar (Radhiallahu ‘Anhu) also said, “The person who fears Allah will never vent his anger and will never do as he pleases. Had it not been for the Day of Qiyaamah, matters would have been very much different to what you see." 
It was Umar (Radhiallahu ‘Anhu) who said, "The person who is just to people despite the hardship he has to endure, will be granted success in all his endeavours. Humbling oneself in obedience to Allah is closer to righteousness than to desiring honour." 
Maalik reports that the report reached him that Umar (Radhiallahu ‘Anhu) said, “A man's respect lies in his Taqwa, his honour in his Deen and his manhood in his character. Courage is the antithesis of cowardice because while a courageous man will fight to defend those he knows as well those he does not know, the coward will flee from defending even his own parents. While people see respect in wealth, true honour really lies in Taqwa. I am not better than a Persian, a non-Arab or a common farmer except by virtue of Taqwa (the best will be the one with the most Taqwa)." 
Sufyaan Thowri reports that Umar (Radhiallahu ‘Anhu) once wrote to Abu Moosa Ash'ari (Radhiallahu ‘Anhu) saying, "Wisdom is not something that comes with age but it is a gift that Allah grants to whoever He pleases. Ensure that you always stay away from shameful acts and evil character."
Umar (Radhiallahu ‘Anhu) once wrote to his son Abdullaah (Radhiallahu ‘Anhu) saying, "I advise you to always adopt Taqwa because Allah will always protect the one who has Taqwa. Allah suffices for the one who trusts in Him, He rewards the one who gives Him a loan and increases His bounties on the one who is grateful. Taqwa should always be your prime objective, the foundation of all your actions and the polish of your heart. Remember that there is no deed for the one who makes no intention, there is no reward for the one who does not intend it, there is no benefit in the wealth of the one who has no compassion and there can be nothing new for the one who has nothing old."
Ja'far bin Zabrqaan reports that in a letter to one of his governors, Umar (Radhiallahu ‘Anhu) concluded with the words, ''Take stock of yourself during times of prosperity before difficulties take stock of you because the one who takes stock of himself during times of prosperity will ultimately by happy and the envy of others. As for the one who has been distracted by the world and who has made sin his occupation, he will ultimately have only regret and grief. Take heed of the advice given to you so that you may refrain from that which you are being prevented from doing." 
In a letter to Mu'aawiya bin Abu Sufyaan (Radhiallahu ‘Anhu), Umar (Radhiallahu ‘Anhu) stated, "Hold fast to the truth and it will reveal to you the status of the people of the truth. Ensure also that you always pass judgement by the truth. Was Salam."
 Deenowri, as quoted in Kanzul Ummaal(VQL8 Pg.208).
 Bayhaqi. as quoted in Kanzui Ummaal (Vo1.8 Pg.208).
 Khateeb. Ibn Asaakir and Ibn Najjaar, as quoted in Kanzul Ummaal (Vo1.S Pg.23lJ).
 Abu NU'aym in his Hilya (Vol. I Pg.55).
 Ibn Abi shaybah. Ibn Abi Dunya, Kharaa·iti, Bayhaqi and Ibn Asaakir, as quote4 in Kanzu/ Ummaa/ (Vol.8 Pg.235).
 Tabraani in his Awsat. Hayt:hami (Vo1.l 0 Pg.302) has commented on the chain of narrators.
 Ibn Abi Dunya, Askari, Bayhaqi and others, as quoted in Konzul Ummaal (VoL8 Pg.235).
 Abu NU'aym in his Hilya (VoU Pg.55).
 Abu Nu'aym in his Hilya (VoU Pg.51).
 Ibn Abi Dunya, oeenowri in his Mujaalasah and Haakim in his Kuna, as quoted in Konzu/ Ummaal (VoI8. Pg.235).
 Kharaa'iti and others, as quoted in Konzu/ Ummaa/(VoI.8 Pg.235).
 Ibn Abi Shaybah, Askari, Ibn ]areer, Daar Qutni and Ibn Asaakir, as quoted in Kanzu/ Ummaal (VoLS Pg.235).
 Ibn Abi Dunya and Deenowri, as quoted in Kanzul Ummaal (Vo1.8 Pg.235).
 IbnAbi Dunya, Abu Bakr Sowli and Ibn Asaakir, as quoted in KilnzU! Ummaal(Vol.8 Pg.207).
 Bayhaqi in his Zuhd and Ibn Asaakir, as quoted in Kanzul Ummaal (Vol.8 Pg.207).
 Abul Hasan Rizqawi in his Juz, as quoted in KilnZlll Ummaal (Vol.8 Pg.208).
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