Narrated Abu Huraira: While we were sitting with the Prophet Surat Al-Jumu'a was revealed to him, and when the Verse, "And He (Allah) has sent him (Muhammad) also to other (Muslims).....' (62.3) was recited by the Prophet, I said, "Who are they, O Allah's Apostle?" The Prophet did not reply till I repeated my question thrice. At that time, Salman Al-farisi was with us. So Allah's Apostle put his hand on Salman, saying, "If Faith were at (the place of) Ath-Thuraiya (pleiades, the highest star), even then (some men or man from these people (i.e. Salman's folk) would attain it."
(Book 60, Hadith 420,Sahih Bukhari)
Allamah Jalaluddin Suyuti [r.h] writes:
اقول قد بشر صلى اللّه عليه واله وسلم بالامام ابى حنيفه فى الحديث
"I say that Prophet Muhammed [s.a.w] has given the glad tidings of Imam Abu Hanifa [r.h] in this hadith [of Abu Hurayra] [r.a]."
[Tabyeed al-Sahifa, page 403]
Allamah ibn Hajar Makki [r.h] has also quoted this view of Allamah Suyuti [r.h] in al-Khayrat al-Hisaan.
Imam Shah Waliullah Muhaddith Dehlwi [r.h] has mentioned in his Maktubaat that Imam Abu Hanifa [r.h] falls under the above mentioned hadith. [Kalmat al-Tayyibaat, page 168]
Famous Wahabi scholar Nawab Saddiq Hassan Khan [r.h]( Who later accepted Islam) also wrote that this hadith refers to Imam Abu Hanifa [r.h]. [Ithaf al-Nubla, page 424]
Courtsey: Shaykh Salman
Imam Abu Hanifa Numan ibn Thabit ibn Numan ibn Marzuban , called "The Imam" by Abu Dawud, and "The Imam, one of those who have reached the sky" by Ibn Hajar, he is known in the Islamic world as Imam Al Azam (The greatest Imam) and his school has the largest number of followers among the four schools of Ahly Sunna. He was a successor and met such Sahaba as Anas bin Malik, Sahl bin Sa’d, Ibn Abi Awfa etc. He was the first to organize Fiqh in written form under subheadings due to which Imam Shafi said:
(intro taken from Sunnipath.com)
Al Nasu Iyalun Ala Abi Hanifa Fi Al Fiqh
People are the dependents of Abu Hanifa in Fiqh. 
Imam Abu Hanifa was born in Kufa, and this is the opinion of the majority of the Ulema, in the year 80 Ah during the reign of Caliph Abdul Malik ibn Marwan ibn Al Hakim. His coming was predicted by the Prophet (Allah Bless him and grant him peace). Abu Nuaym narrates in his Hiyat al Awliya, Bukhari and Muslim narrate from another Sanad from Abu Hurayrah (Allah be pleased with him), Abu Bakr Shirazi narrates in his Kitab Alqab, Tabarani from Sa’d bin Ubaidah (Allah be pleased with him) and Ibn Masud (Allah be pleased with him) that the Prophet (Allah Bless him and grant him peace) said:
---If Ilm was suspended from Pleiades and the Arabs are unable to reach it, then a man from the sons of Persia will be able to reach it.
Imam Suyuti mentions that the Ulema have stated that that these hadith are in favor of Imam Abu Hanifa and are authentic.
However, it was not only the Ilm of Imam Abu Hanifa that made him such a great man, but It was also his constant Ibadat and fear of Allah, his endeavor to purify himself from all worldy things, his asceticism and his forbearance in the face of difficulties. That is what made Imam Abu Hanifa Imam Al Azam.
1. Imam Abu Hanifas constant Ibadat, recitation of the Quran and Night Vigils:
Imam Dhahabi says that Imam Abu Hanifas Ibadat, in particular his Tahajjud prayers and recitation of the Quran, are established by Khabare Mutawattir, which means that it is a fact so commonly narrated by the tongues of people that it would be impossible to deny. Sufyan ibn Uyannah is said to have remarked:
In our time from amongst those who came to visit Mecca not a single soul could surpass Abu Hanifa in Salah.
Hammad, the son of Imam Abu Hanifa, narrates that Hasan ibn Ammarah said:
May Alah have mercy on Abu Hanifa. For thirty years he fasted and for fourty years he did not sleep at night.
Like Imam Bukhari, Imam Abu Hanifa used to finish the Quran 60 times in Ramadhan. He was so pious and scrupulous that he used to recite the whole Quran in one Raka, May Allah grant him the highest abode.
Zafir ibn Sulayman says:
Abu Hanifa used to spend much of the night in one Raka and in that one Raka he used to recite the entire Quran.
Ibrahim ibn Rustum Al Marwazi said:
Four are the Imams that recited the entire Quran in a single Raka: Uthman ibn Affan (Allah be pleased with him), Tamim Al Dari, Said ibn Jubayr, and Abu Hanifa.
Ibn K’as narrates:
Due to his excessive Ibadat Abu Hanifa used to lo ok like a worn out rag.
2. Imam Abu Hanifas Allah-consciousness and withdrawal from futile things:
Khatib Baghdadi narrates that Asad ibn Amir said:
Overcome by fear of Allah Imam Abu Hanifas weeping could be heard right outside. On hearing his excessive weeping, even his neighbors were overwhelmed with pity for him.
Yahya ibn Mai’n says that he heard Yahya ibn Said sayd:
By Allah! We sat in the company of Abu Hanifa and heard many religious issues from him. I swear by Allah! When I looked at his face I used to be overcome with firm conviction that this man is very fearful of Allah.
Saymari narrates that Bakr Al Abid said:
I saw Imam Abu Hanifa performing Salah at night. He was weeping and praying, “Oh Allah have mercy on me on the day you resurrect me.”
Qadi Abul Qasim narrates that Abu Nuaym ibn Dukain said:
Imam Abu Hanifa was very wary of people. He used to speak to them only when questioned. He did not ponder over or listen to futile things.
3. Imam Abu Hanifas piety, asceticism, forbearance and trustworthiness:
Ibn Dukain narrates:
Imam Abu Hanifa was very pious and trustworthy.
Muhammad ibn Ayman narrates that when Abdullah ibn Mubarak was asked about Imam Abu Hanifa he replied:
Can anyone ever be like him? He was tried with lashes  but he exercised forbearance.
Abdullah ibn Mubarak said regarding Imam Abu Hanifa:
What can be said about a man who was presented with all the material wealth and chattels of the dunya but rejected it all? A man who was severely lashed but bore it with patience?
Nadr ibn Muhammad said:
I haven’t witnessed anyone as abstinent and pious as Imam Abu Hanifa.
Hasan ibn Ziyad said
Abu Hanifa never accepted any gift or favor from the rulers and kings (although he was offered much)
Zaid ibn Zarqa narrates that a man once remarked to Abu Hanifa:
This dunya is being presented to you then why don’t you accept it since you are a family man?
Imam Abu Hanifa replied:
Allah is sufficient to attend to the needs of my family. As for me, my monthly expenses amount to just two dirhams. Why should I accumulate wealth for them when I will be questioned about accumulating it? Whether they are obedient to him or disobedient does not make a difference to me being questioned since Allah’s sustenance reaches both the obedient and disobedient, “And in the sky is your sustenance and that which you are being promised (Zariyat: 22)
4. Opinions of other great Ulema regarding Imam Abu Hanifa:
a. Abu Jafar Muhammad ibn Ali ibn Hussain ibn Fatima Bint Prophet Muhammad:
Abu Jafar Muhammad ibn Ali the great grandson of the Prophet Muhammad (Allah Bless him and grant him peace) said:
How commendable are Abu Hanifas manners and how sublime is his skill in Fiqh!
b. Imam Malik ibn Anas ibn Malik
The founder of the Maliki school of thought, Imam Malik is reported to have said when asked about Imam Abu Hanifa:
Yes, I saw him and I saw him to be a man of such caliber that if he claims that this pillar of wood is made of gold he will prove it to you!
c. Imam Shafi Al Hashmi
The founder of the Shafi school of thought, Imam Shafi is reported to have said:
The person who wishes to excel in Fiqh is bound to be in need of Imam Abu Hanifa. He was a person who was divinely guided with Fiqh by Allah. I have not seen a greater Faqih then him.
d. Imam Ahmad ibn Hanbal
The founder of the Hanabli school of thought, Imam Ahmad is reported to have said:
In terms of Ilm, piety, abstinence from this dunya and preference of the hereafter, Abu Hanifa occupied such a lofty position that no one else could reach. May Allah shower his mercy on him!
5. Imam Abu Hanifas Death:
Imam Abu Hanifa died a martyr in prison in the year 150 Ah. He was poisoned on the orders of the Caliph Mansur after being lashed and thrown in jail for refusing the post of Chief Justice. According to Yaqub ibn Shaybah he died while in a state of sujud. May Allah have mercy on him and grant him the best of Rewards!
 The main source of this biography is Uqudul Jamman Fi Manaqibil Imami Al Azam Abi Hanifata An Numan by Muhaddith Allamah Shamsudin Muhammad ibn Yusuf Dimashqi. It was translated in Urdu by Maulana Abdullah ibn Bastawi Madani. I advise everyone to get this valuable book as it has also been translated into English.
 Narrated by Ismail ibn Hammad ibn Abu Hanifa
 Narrated by Imam Dhahabi in Tadkhirat al Huffaz.
 Imam Abu Hanifa was lashed by the Caliph for refusing the post of chief justice.