The Night Prayer is in Sets of Two's
Question :
Some of the Imams combine four Rak'ahs or more in the Tarawih prayer with only one Tasleem (concluding by saying As-Salamu Alaikum wa Rahmatullah) and no sitting between two Rak'ahs. They claim that this is the Sunnah. Is there any basis for this act in our pure Islamic law?
Answer:
This act is not legislated. Rather, it is disliked or even forbidden according to most of the people of knowledge.
This is due to the Prophet's statement:
"The night prayer is two, two (i.e., sets of two's)."
The authenticity of this Hadith is agreed upon from a narration of Ibn 'Umar. This is also due to what is confirmed from 'A'ishah as she said:
"The Prophet used to pray 11 Rak'ahs during the night, and he would make the Tasleem after every two Rak'ahs and make Witr (odd number prayer) with one Rak'ah (i.e., at the end)."
This Hadith's authenticity is agreed upon and the Hadiths with this meaning are numerous.
In reference to the famous Hadith of 'A'ishah where she said:
"Verily, the Prophet used to pray four Rak'ahs at night, and do not even ask about their beauty and length. Then, he would pray four Rak'ahs, and do not even ask about their beauty and length."
This Hadith is agreed upon (by Al-Bukhari and Muslim) and it means that he would make the Tasleem between every two Rak'ahs. It does not mean that he would make all the four Rak'ahs with only one Tasleem. This is due to what she said in the previous Hadith and also due to what is confirmed from him in his saying that the night prayer is two, two; as was mentioned previously. Some Hadiths affirm the others and some of them explain the others. Thus, it is obligatory on the Muslim to take them all and interpret Al-Mujmal (that which has more than one possible meaning) by Al-Mubayyin (that which clarifies). And Allâh is the Giver of success.
Source:
Ash-Shaykh Ibn Baz
Fatawa Islamiyah, Vol. 3 Pages 316- 317