All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
It is more appropriate for a praying person to say the confirmed supplication in the Witr Qunoot that the Prophet taught Al-Hasan ibn ‘Ali, may Allaah be pleased with both of them. The wording of this supplication is as follows:
“Allaahumma ihdinee feeman hadayt, wa 'aafinee feeman 'aafayt, wa tawallanee feeman tawallayt, wa baarik lee feemaa a'atayta, wa qinee sharra maa qadhayt, innaka taqdhee walaa yuqdhaa 'alayk, innahu laa yathillu man waalayt wa la ya'izzu man 'aadayt, tabaarakta rabbanaa wa ta'aalayt."
"O Allaah, guide me along with those whom You have guided, pardon me along with those whom You have pardoned, be an ally to me along with those whom You are an ally to, and bless for me that which You have bestowed upon me. Protect me from the evil that You have decreed, for verily You decree and none can decree over You. For surely he whom You show allegiance to is never abased, and he whom You take as an enemy is never honored. Blessed and Exalted are You, our Lord.” [Abu Daawood and At-Tirmithi]
The Fiqh Encyclopedia reads, “An-Nawawi said, 'Know that it is not an obligation to say a specific supplication in Qunoot according to the chosen opinion. Any supplication that the praying person says is acceptable (i.e. achieves the purpose of the Qunoot supplication); even if he only says one verse or some verses from the Quran that include words of supplication, then the Qunoot is achieved by this, but what is mentioned in the Sunnah is better…”
Regarding someone who makes a mistake in the Qunoot supplication or leaves a word from it, then this does not invalidate the Witr prayer; rather, if one does not say the Qunoot supplication at all, his Witr prayer is valid and he is not required to do anything.
Shaykh Ibn Taymiyyah said:
“With regard to the Qunoot supplication of the Witr prayer, then the scholars have three different opinions about it.
The first view is that it is not recommended under any circumstances because it is not proven that the Prophet said the Qunoot supplication in the Witr prayer.
The second view is that the Qunoot supplication is desirable throughout the year, as has been reported from Ibn Mas’ood and others, because in the Sunan, the Prophet taught Al-Hasan ibn ‘Ali a supplication to say in the Witr Qunoot.
The third view is that the Qunoot is only in the second half of the month of Ramadaan because Ubayy ibn Ka'b used to do so. In fact, the Witr Qunoot is a kind of supplication that is well-known in prayer, and if one wishes to say it, he may do so, and if one wishes to not say it, then he may do so as well, in the same manner that a person is given the choice to pray the Witr prayer with three Rak’ahs (units of prayer), or five Rak’ahs, or seven Rak’ahs. Also, one has the choice when he prays the Witr prayer three Rak’ahs, he may pray them continuously with one Tashahhud or he may pray them separately, i.e. he prays two Rak’ahs and concludes the prayer and then he prays one Rak’ah. Also, he has the choice regarding the Qunoot supplication, he may say it if he so wishes, and he may leave it if he so wishes.
Moreover, if he leads the prayer in the Qiyaam (night prayer) of Ramadaan, then if he says the Qunoot supplication throughout the entire month of Ramadaan, then this is good, and if he only says it in the second half of Ramadaan, then this is also good. If he does not say the Qunoot at all, then this is also good.”
Allaah knows best.