Imam Ahmad (may Allah have mercy on him) said: Whoever neglects Witr is a bad man whose testimony should not be accepted. This indicates that Witr prayer is something that is confirmed.

Witr prayer is prayed between Isha prayer and dawn (fajr). The Prophet (peace and blessings of Allah be upon him) said: “Allah has prescribed for you a prayer (by which He may increase your reward), which is Witr; Allah has enjoined it for you during the time between ‘Isha’ prayer until dawn begins.” Narrated by al-Tirmidhi, 425; classed as saheeh by al-Albaani in Saheeh al-Tirmidhi.

The hadeeth of Jaabir (may Allah be pleased with him) who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: “Whoever fears that he will not get up at the end of the night, let him pray Witr at the beginning of the night, but whoever thinks that he will be able to get up at the end of the night, let him pray Witr at the end of the night, for prayer at the end of the night is witnessed (by the angels) and that is better.” Narrated by Muslim, 755.

The minimum number of rak’ahs for Witr is one rak’ah, because the Prophet (peace and blessings of Allah be upon him) said: “Witr is one rak'ah at the end of the night.” Narrated by Muslim, 752. And he (peace and blessings of Allah be upon him) said: “The night prayers are two (rak’ahs) by two, but if one of you fears that dawn is about to break, let him pray one rak’ah to make what he has prayed odd-numbered.” Narrated by al-Bukhari, 911; Muslim, 749. If a person limits himself to praying one rak’ah, then he has performed the Sunnah. But Witr may also be three or five or seven or nine.

If a person prays three rak’ahs of Witr this may be done in two ways, both of which are prescribed in sharee’ah:

1. To pray them one after another, with one tashahhud, because of the hadeeth of ‘Aa’ishah (may Allah be pleased with her) who said: The Prophet (peace and blessings of Allah be upon him) used not to say the tasleem in the (first) two rak’ahs of Witr. According to another version: “He used to pray Witr with three rak'ahs and he did not sit except in the last of them.” Narrated by al-Nasaa’i, 3/234; al-Bayhaqi, 3/31. al-Nawawi said in al-Majmoo’ (4/7): it was narrated by al-Nasaa’i with a hasan isnaad, and by al-Bayhaqi with a saheeh isnaad.
2. Saying the tasleem after two rak'ahs, then praying one rak’ah on its own, because of the report narrated from Ibn ‘Umar (may Allah be pleased with him), that he used to separate the two rak'ahs from the single rak'ah with a tasleem, and he said that the Prophet (peace and blessings of Allah be upon him) used to do that. Narrated by Ibn Hibbaan (2435); Ibn Hajar said in al-Fath (2/482): its isnaad is qawiy (strong).

   It is also narrated that the prophet used to also pray 5 and 7 rak’ah’s of Witr in which he would make them continuous without any tashahhud in the middle. However when he prayed 9 rak’ahs he used to make tashahhud in the 8th rak’ah as well.

All these ways of offering Witr prayer have been mentioned in the Sunnah, but the best way is not to stick to one particular way; rather one should do it one way one time and another way another time, so that one will have done all the Sunnahs.

And Allah knows best.