Imaam al-Hajjaawee said in his book ‘Zaadul-Mustaqni`’ [a very summarised book on the Fiqh methodology of Imaam Ahmad rahimahullaah]:
“And the Taraaweeh [prayer] is twenty units (rak`ahs).”
Shaykh Muhammad bin Saalih al-Uthaymeen rahimahullaah said in his explanation ‘ash-Sharhul Mumti`’ vol. 4 pp. 65-71:
“And the Taraaweeh prayer is an emphasised Sunnah, because it is from the standing in Ramadaan. And the Prophet sallAllaahu `alaihi wa sallam said: “Whoever stands [in prayer] in the month of Ramadaan out of sincere faith and hoping for Allaah’s reward, then all his previous sins will be forgiven.”
And it was called ‘Taraaweeh’ (lit. sitting for rest), because it is from their customary practice when they prayed four units, they would sit for a short while to rest – based on the narration of `Aaishah radiyAllaahu `anhaa: “That the Prophet sallAllaahu `alaihi wa sallam used to pray four units, so do not ask me about their beauty and their length, then he would pray four units, so do not ask me about their beauty and their length, then he would pray three units.” The point being that she said: “He would pray four then…” And the word ‘then’ indicates: order with a delay, and that there was a break between the first four, the second four, and the last three.
And with each set of four he gives the tasleem (saying ‘as-Salaamu `alaikum wa rahmatullaah’ to end the prayer) after every two units, as was explicitly mentioned in the narration of `Aaishah: “That he would pray eleven units, giving tasleem after every two units.”
And this is in opposition to that which some of the students of knowledge imagine: that they think the first four are to be gathered together with a single tasleem, and the second four are to be prayed in a like manner. And this delusion [of theirs] comes partly from their lack of following [and gathering] between all of the chains for this narration [of `Aaishah]; and partly because of their failure to see the narration of Ibn `Umar – radiyAllaahu `anhumaa –, which is: “That the Prophet sallAllaahu `alaihi wa sallam was asked about the night prayer so he said: ‘In twos, in twos.’”
Based upon this it is binding to understand every [general] unrestricted narration mentioning the number of units to be prayed at night in light of this restricting [specific] text. And it is: that they are to be prayed in twos.
As for those [texts which] explicitly mention not doing so [i.e. not praying in twos] – such as praying the Witr prayer with five, seven, or nine units – then they are specific and [separate] from the generality of [the ruling of] this narration.
So if it is said: “Why did Aaishah say: ‘He would pray four, then he would pray [another] four’?”
We say the answer is: because he combined the first four at the same time; so he prayed two, then immediately prayed the other two. Then he sat and waited for a period, then he resumed and prayed two units – following them with two more units. Then he sat for a[nother] period, then he prayed three.
So the Salaf (pious predecessors) extracted from this: that the four units are to be prayed with two tasleems, then the people rest, then they pray four [more], then they rest, then they pray three – if they were to pray eleven units.
As for his [the author, al-Hajjaawee’s] saying: ‘Twenty units’ – if we were to add and complete that with the lowest number of units for Witr – we would end up with twenty-three units. Because Taraaweeh would be prayed with twenty units, then Witr with three units. So the total would be twenty three units. This is the standing in Ramadaan.
So what is the proof?
The evidence is that which Aboo Bakr `Abdul-Azeez reported in ‘ash-Shaafee’ from Ibn Abbaas ‘that the Prophet sallAllaahu `alaihi wa sallam would pray twenty units in the month of Ramadaan.’
However this narration is weak, and incorrect as being from the Prophet sallAllaahu `alaihi wa sallam. And that which is authentically reported from him – via the one who was most knowledgeable regarding his affairs during the night – Aaishah, the Mother of the Believers, may Allaah be pleased with her that she said: “He would not increase upon eleven units.” When asked regarding the prayer of the Prophet sallAllaahu `alaihi wa sallam in Ramadaan; she said: “He would not increase upon eleven units inside of Ramadaan or outside of Ramadaan.” And this is an explicit text from Aaishah, and she was from the most knowledgeable of people regarding that which he used to do at night.
So if someone was to say: “It has been mentioned regarding Umar ‘that he ordered Ubayy bin K`ab to lead the people in prayer with twenty-three units’.”
We say: this is also not authentic, rather it has been reported that Yazeed bin Roomaan said: “The people used to pray twenty-three units in Ramadaan during the time of Umar.” However Yazeed bin Roomaan did not witness the time of Umar – resulting in their being a breakage in [the chain of] this narration.
Furthermore this narration does not mention that Umar knew of that. And that which was done in the time of Umar is not a proof, unlike that which was carried out in the time of the Messenger – if he did not criticise it – then it is a proof; because the Messenger sallAllaahu `alaihi wa sallam if he knew something [and did not criticise it] then he approved of it, and if he did not know of it then the revelation approved of it. However in the time of Umar there was no revelation – so we do not describe Umar as being pleased with it unless it is clearly attributed to Umar. However [Imaam] Maalik rahimahullaah reports in ‘al-Muwatta’ with a chain of narration from the most authentic chains of narration ‘That Umar bin al-Khattaab radiyAllaahu `anhu ordered Tameem ad-Daaree and Ubayy bin K`ab to stand with the people in prayer [i.e. to lead the people] with eleven units.”
So this is a clear evidence, and an order from Umar radiyAllaahu `anhu – and it is what is befitting from him – may Allaah be pleased with him, as he was from the most ardent of the people in clinging to the Prophetic way. So if the Messenger sallAllaahu `alaihi wa sallam did not exceed upon eleven units, then we hold that Umar bin al-Khattaab radiyAllaahu `anhu would cling tightly to this number.
Based upon this: what is correct regarding this issue is: that the Sunnah [Prophetic way] regarding the Taraaweeh is that it is eleven units. Ten units are to be prayed with even numbers [i.e. in twos], and one by itself as Witr.
And the Witr is as Ibnul-Qayyim mentioned: It is the one [single unit] – not the units that preceded it.” So that which preceded it is Qiyaamul-Layl (Standing [in prayer] in the night), and the Witr is the one [single unit].
And if a person were to pray the Witr as three – after the ten – so that his prayer was thirteen units, then there is no harm. Because this is also authentically established from a narration of Abdullaah bin Abbaas radiyAllaahu `anhumaa: ‘That the Prophet sallAllaahu `alaihi wa sallam prayed thirteen units.’
So this is the Sunnah.
Despite this, if a person were to pray twenty-three, or more than that – then he is not to be criticised. However, if he requested the people of the mosque not to increase upon the number that is Sunnah [authentically established from the Prophet sallAllaahu `alaihi wa sallam], then that is something they should agree with foremostly, because the proof is with them. But if they [the people] were to remain quiet and were pleased with [the Imam] leading them in prayer with ninety-nine units, then there is no harm in that.
 Agreed upon. Reported by al-Bukhaaree no. 2009; & Muslim no. 759.
 Agreed upon. Reported by al-Bukhaaree no. 1147; & Muslim no. 738.
 Agreed upon. Reported by al-Bukhaaree no. 990; & Muslim no. 749.
 Such as: the narration reported by an-Nasaaee no. 1698 from a narration of Aaishah that the Prophet sallAllaahu alaihi wa sallam would not give the Tasleem for the two units of witr. [Shaykh al-Albaanee rahimahullaah graded it as ‘Shaath’ – contradictory to that which is more authentic].
And the narration of Muslim no. 737 that the Prophet sallAllaahu `alaihi wa sallam would pray thirteen units at night, and he prayed Witr with five units – not sitting except at the end of them.
And from a narration reported by Ibn Maajah no. 1192 that the Prophet sallAllaahu `alaihi wa sallam would pray the Witr with five or seven units, not separating between them with Salaam (i.e. tasleem) nor any speech. [Shaykh al-Albaanee rahimahullaah said ‘Saheeh’, authentic.]
 Reported by Ibn Abee Shaybah in his ‘Musannaf’ 2/294; and al-Khateeb in ‘al-Muwaddhih’ 1/219; and al-Bayhaqee in his ‘Sunan’ 2/496. And al-Bayhaqee said: “It is weak”. Also declared weak by az-Zayla`ee in ‘Nasb ar-Raayah’ 2/153; and as-Suyootee in ‘al-Haawee’ 2/73; and al-Haafidh in ‘al-Fath’ 4/205-206.
 Agreed upon. Reported by al-Bukhaaree no. 1147; & Muslim no. 738.
 Reported by Maalik in ‘al-Muwatta’ 1/138; & al-Bayhaqee 2/496; & al-Marwazee in ‘Qiyaamul-Layl’ pp. 91.
 Yazeed bin Roomaan. He was: Aboo Rooh al-Asadee al-Madanee, the freed slave of aali-Zubayr. He was from the Taabi`een (the generation after the Companions of Allaah’s Messenger sallAllaahu `alaihi wa sallam), reliable. The six books (Bukhaaree, Muslim, at-Tirmidhee, Abu Dawud, Ibn Maajah, an-Nasaaee) and others all report from him, he died 130H. See: ‘Tahdheebut-Tahdheeb’ 11/325.
And it has been reported from as-Saaib bin Yazeed that he said: “They [i.e. the people] would stand in Ramadaan during the time of Umar bin al-Khattaab radiyAllaahu `anhu with twenty units.” Reported by Abdur-Razzaaq 7730 and 7733; & al-Firyaabee in ‘as-Siyaam’ 1/76; & al-Bayhaqee in ‘as-Sunan’ 2/496; & al-Marwazee in ‘Qiyaamul-Layl’ pp. 91; & `Abdur-Razzaaq has the wording: ‘Twenty-one [units]’. And it’s chain of narration is authentic.
And Yahyaa bin Sa`eed reported: ‘That Umar bin al-Khattaab radiyAllaahu `anhu ordered a man to pray twenty for them. [i.e. to lead them in prayer]’. Reported by Ibn Abee Shaybah 2/393 – however in it[s chain] there is a breakage; as occurs in ‘at-Tuhfah‘ 2/85 of al-Mubaarakfooree.
And Abul-Hasnaa reported ‘that `Alee ordered a man to lead them in prayer during Ramadaan with twenty.’ Reported by Ibn Abee Shaybah 2/393; & al-Bayhaqee 2/497 and he declared it to be weak.
And it has been reported from `Abdul `Azeez bin Rafee` that he said: “Ubayy used to lead the people in prayer during Ramadaan with twenty, and he would pray the Witr with three.” Reported by Ibn Abee Shaybah 2/293; however it has a breakage in its chain of narration – as occurs in ‘at-Tuhfah’ 2/75.
And Zayd bin Wahb reported ‘that Abdullaah bin Masood used to lead us in prayer during Ramadaan … with twenty units, and he would pray the Witr prayer with three.” Reported by Ibn Nasr in ‘Qiyaamul-Layl’ pp. 91; however there is a break in its chain – as occurs in ‘at-Tuhfah’ 2/75.
And al-Marwazee reported pp. 91; & Ibn Abee Shaybah 2/393 from a narration of Ataa bin Abee Rabaah that he said: “I witnessed the people praying twenty units during Ramadaan, and they would pray the Witr with three.” And they (al-Marwazee & Ibn Abee Shaybah) also report from Shutayr bin Shakal – and he was from the companions of Abdullaah [bin Masood] ‘that he would lead them in prayer with twenty, and pray Witr with three.’
From the pious predecessors (Salaf) that did so [i.e. prayed twenty for Taraaweeh] – as reported by the previous references – are: al-A`mash, and Sa`eed bin Jubayr, and Aboo Mijlaz, and Ibn Abee Mulaykah, and Abul-Bakhtaree, and other than them. And this is clear proof of them not limiting it.
 Muwatta Maalik 1/115; & al-Bayhaqee 2/496.
 Zaadul-Ma`aad 1/329
 Agreed upon. Reported by al-Bukhaaree no. 1138; & Muslim no. 764.