What Is Qunut?
Question

I would like to ask about the Qunut in Salat (raising hand after ruku’). Was that the common practice of the Prophet (peace and blessings be upon him) or was it exceptional as the situation arose? Please respond to me because the imam of our masjid said the Prophet once asked which of the salat is best? He (peace be upon him) replied: ‘the one which has longer Qunut.’
Praise be to Allah.What is Qunut?
Qunut, according to the definition of the fuqaha, “is the name of a du’a (supplication) offered during prayer at a specific point while standing.” 
When should Qunut be recited?
It is prescribed in the Witr prayer after the ruku’ (bowing), according to the more correct of the two scholarly opinions. 
If a calamity (nazilah) befalls the Muslims , it is prescribed to say Du’a al- Qunut after standing up from ruku’ in the last rak’ah of each of the five daily obligatory prayers, until Allah relieves the Muslims of that calamity. (See Tashih al-Du’a by Shaykh Bakr Abu Zayd, p. 460). 
Qunut in Fajr prayer all the time, in all circumstances: Valid?
With regard to saying Du’a al-Qunut in Fajr prayer all the time, in all circumstances, there is no sahih report that the Prophet (peace and blessings of Allah be upon him) singled out Fajr for Qunut, or that he always recited it in Fajr prayer. Rather what is proven is that he (peace and blessings of Allah be upon him) said Du’a al-Qunut at times of calamity with words that were appropriate to the situation . 
He said Du’a al-Qunut in Fajr and in other prayers, praying against Ra’l, Dhakwan and ‘Usayyah for killing the Quran-readers whom the Prophet (peace and blessings of Allah be upon him) had sent to them in order to teach them their religion. 
And it was proven that he prayed in Fajr prayer and other prayers for the weak and oppressed believers, that Allah would save them from their enemies. But he did not do that all the time. The Rightly-Guided khalifas after him followed the same practice. 
It is better for the imam to limit Qunut to times of calamity, following the example of the Messenger of Allah (peace and blessings of Allaah be upon him), as it was proven that Abu Malik al-Ash’ari said: “I said to my father, ‘O my father, you prayed behind the Messenger of Allah (peace and blessings of Allah be upon him) and behind Abu Bakr, ‘Umar, ‘Uthman and ‘Ali (may Allah be pleased with them). Did they say Du’a al-Qunut in Fajr?’ He said, ‘O my son, this is a newly-invented matter.’” (Narrated by the five, apart from Abu Dawud; classed as sahih by al-Albani in al-Irwa, 435). The best of guidance is the guidance of Muhammad (peace and blessings of Allah be upon him). 
And Allah is the Source of strength. May Allah send blessings and peace upon our Prophet Muhammad and upon his family and Companions. (al-Lajnah al-Daimah li’l-Buhuth al-‘Ilmiyyah wa’l-Ifta, 7/47) 
Is there a specific wording for Qunut?
If you ask, is there a specific wording for Qunut during Witr prayer, or Qunut at times of calamity? 
The answer is: for Du’a al-Qunut in Witr prayer a number of wordings have been narrated, including the following: 
1 – The version which the Messenger of Allah (peace and blessings of Allaah be upon him) taught to al-Hasan ibn ‘Ali (may Allah be pleased with him), which is: 
“Allaahumma ihdini fiman hadayta wa ‘afini fiman ‘afayta wa tawallani fiman tawallayta wa barik li fima a’tayta, wa qini sharra ma qadayta , fa innaka taqdi wa la yuqda ‘alayk, wa innahu la yadhillu man walayta wa la ya’izzu man ‘adayta, tabarakta Rabbana wa ta’alayta la manja minka illa ilayk
(O Allah, guide me among those whom You have guided, pardon me among those whom You have pardoned, turn to me in friendship among those on whom You have turned in friendship, and bless me in what You have bestowed, and save me from the evil of what You have decreed. For verily You decree and none can influence You; and he is not humiliated whom You have befriended, nor is he honoured who is Your enemy. Blessed are You, O Lord, and Exalted. There is no place of safety from You except with You).” (Narrated by Abu Dawud, 1213; al-Nasai, 1725; classed as sahih by al-Albani in al-Irwa, 429). 
It was narrated from ‘Ali ibn Abi Talib that the Prophet (peace and blessings of Allaah be upon him) used to say at the end of Witr: 
“Allahumma inni a’udhu bi ridaka min sakhatika wa bi mu’afatika min ‘uqubatika wa a’udhu bika minka, la uhsi thanaan ‘alayka anta kama athnayta ‘ala nafsika (O Allah, I seek refuge in Your pleasure from Your wrath and in Your forgiveness from Your punishment. I cannot praise You enough; You are as You have praised Yourself.” (Narrated by al-Tirmidhi, 1727; classed as sahih by al-Albani in al-Irwa, 430; Sahih Abi Dawud, 1282). 
Then he should send blessings upon the Prophet (peace and blessings of Allah be upon him) as it was narrated that some of the Sahabah (may Allah be pleased with them) – including Ubayy ibn Ka’b and Mu'adh al-Ansary (may Allah be pleased with them) – did that at the end of Qunut al-Witr. (See Tashih al-Du’a by Shaykh Bakr Abu Zayd, p. 460). 
Qunut at times of calamity (Qunut al-Nazilah) 
When praying Qunut at the time of calamity , one should make supplication as is appropriate to the situation, as it was narrated that the Prophet (peace and blessings of Allah be upon him) cursed some Arab tribes who had betrayed his Companions and killed them, and he prayed for the weak and oppressed believers in Makkah, that Allah would save them.  It was narrated that ‘Umar prayed Qunut with the following words:
“Allahumma inna nasta’inuka wa numinu bika, wa natawakkalu ‘alayka wa nuthni ‘alayka al-khayr, wa la nakfuruka. Allahumma iyyaaka na’budu wa laka nusalli wa nasjudu, wa ilayka nas’a wa nahfid. Narju rahmataka wa nakhsha ‘adhabaka, inna ‘adhabaka al-jadd bil kuffari mulhaq. Allahumma ‘adhdhib il-kafarata ahl al-kitab alladhina yasudduna ‘an sabilika
(O Allah, verily we seek Your help, we believe in You, we put our trust in You and we praise You and we are not ungrateful to You. O Allah, You alone we worship and to You we pray and prostrate, for Your sake we strive. We hope for Your mercy and fear Your punishment, for Your punishment will certainly reach the disbelievers.  O Allah, punish the infidels of the People of the Book who are preventing others from following Your way).” (Narrated by al-Bayhaqi, 2/210; classed as sahih by al-Albani in al-Irwa, 2/170. Al-Albani said: This was reported from ‘Umar concerning Qunut in Fajr, and it seems that this Qunut is Qunut al-Nazilah (Qunut at times of calamity) as is indicated by his praying against the kuffar). 
Other formula for Qunut 
If you ask, can we make du’a using words other than those mentioned here? 
The answer is: 
Yes, that is permissible. Al-Nawawi said in al-Majmoo’ (3/497): “The correct view which was stated definitively by the majority of scholars is that there are no specific words, rather any du’aa’ may be said.” 
The version narrated from ‘Umar is not something that we have to follow, and the Prophet (peace and blessings of Allaah be upon him) did not pray using these words, so there is nothing wrong with adding more to them. Shaykh al-Albani (may Allah have mercy on him) said: “There is nothing wrong with adding more to this, cursing the infidels and sending blessings upon the Prophet (peace and blessings of Allaah be upon him), and praying for the Muslims.” (Qiyam Ramadan by al-Albani, 31). 
Qunut: Before or after Ruku’?
We still have an important question which is: should Du’a al-Qunut be said before ruku’ (bowing) or after? 
The answer is: Most of the ahadith and the opinion of most of the scholars state that Qunut comes after ruku’, but if you say Qunut before ruku’ that is acceptable. So you have the choice of doing ruku’ when you have finished reciting Quran, then standing up and saying “Rabbana wa laka al-hamd” then saying Qunut… or saying Qunut when you have finished reciting Quran, then saying “Allahu akbar” and bowing. Both of these were narrated in the Sunnah. (Shaykh Muhammad ibn ‘Uthaymin (may Allah have mercy on him), al-Sharh al-Mumti’, 4/64) 
Is prayer with a longer Qunut the best?
Note: The questioner says that the best prayer is that which has longer Qunut. Perhaps he is referring to the hadith narrated by Muslim (1257) from Jabir (may Allah be pleased with him), which says that the Prophet (peace and blessings of Allah be upon him) said: “The best of prayer is tool al-qunut (the longest in standing).”
 Al-Nawawi said: “What is meant by qunut here is the standing, according to the consensus of the scholars, as far as I know.”
 So the hadith is not referring to Qunut in the sense of the du’a said after standing up from ruku’, rather it is referring to standing for a long time.
 And Allah knows best.