Some people give the 8 Rakaat Taraweeh daleel from a Daeef hadith by Hadhrat Jaber Radhi Allahu Anhu. Lets see what the Muhaqqiq of Saheeh Ibne Hibban Shoaib Arnaut says about it. Very clearly states that it is Daeef :

“إسناده ضعيف. عيسى بن جارية ضعيف، قال ابن معين: عنده مناكير، وقال النسائي: منكر الحديث، وجاء عنه: متروك، وقال ابن عدي: أحاديثه غير محفوظة، وقال أبو زرعة: لا بأس به. أبو الرسغ الزهراني: هو سليمان بن داود العتكي، ويعقوب القمي: هو ابن عبد اللهالأشعري.
وأخرجه المروزي في “قيام الليل وكتاب الوتر” كما في “مختصره ” للمقريزي، ص 118 عن إسحاق بن إبراهيم، بهذا الإِسناد.
وأخرجه الطبراني في “الصغير” (525) ، وابن خزيمة (1070) ، من طريق يعقوب القمي، بهذا الإِسناد.
قال الهيثمي في “المجمع” 3/172: فيه عيسى بن جارية وثقه ابن حبان، وضعفه ابن معين. وسيرد برقم(2415) ”


Also check:

1. Imam ibn A’adi r.h states: The hadith that is narrated by Isa Bin Jaariya is “not” preserved. ( Tehzeeb At Tehzeeb : 186 /8 , Tehzeeb Al Kamaal : 533 , 534 /14 , Mizaan Ul Aitedaal : 311/3)

2. Imam Aqeeli r.h has classified Isa Bin Jaariya amoungst Da’eef(weak) narrators. (Tehzeeb At Tehzeeb : 186 /8 , Tehzeeb Al Kamaal : 533 , 534 /14 , Mizaan Ul Aitedaal : 311/3)

In the blessed month of Ramadan people try there best to attend the Taraweeh Salaah and they should also do the same with Tahajjud Salaah during Ramadan since both of them are separate and are not the same. Some people claim that they are the same but that is not the truth and in this post we will see some of the daleel that they are both separate from one another. 

1 –Hadhrat Umar Al Farooq Rdh. Al Mutawaffa 23 Hij.

Hadhrat Ameer ul Momineen Umar bin Khattab Rdh. Al Mutawaffa 23 Hij. says:

The prayer for which you sleep (meaning Tahajjud) is Afzal (better) than the one for which you are doing Qayyam (meaning Taraweeh) 

(Saheeh Bukhari : Hadith No. 2010)

Hadhrat Umar Rdh. is encouraging us to offer Tahajjud as well after Taraweeh, since it is a permanent prayer. This is the reason that the Muhaddiseen have classified Taraweeh and Tahajjud separately and have also stated it very clearly.

a. - Imam Abul Wali Sulaimaan al Baaji al Qurtubi Rh. Al Mutawaffa 474 Hij. 

Says about the saying of Hadhrat Umar Rdh. that the Qiyaam in the later part of the night is superior (Afzal) then the part of night in which Qiyaam was before it. 

(Al Muntaqa Lil Baaji : Volume 1 : Page 208)

1. Imam Ibn Qudaama Rahimahullah says:

Some of the people who had ILM says that people of Madina use to do this act (extra 16th Rakaat) because they wanted to be equal to the people of Makkah. In between taraweeh the people of Makkah use to perform 7 circles (of the Holy Qaba) that is why people of Madina use to perform 4 Rakaats Nafil to balance the 7 circles.  (Al Mughni : Volume 2 : Page 602)

In this series of posts i will try to give as much Daleel as possible that Taraweeh is 20 Rakaats and people who say that its either 8 or 11 do not have valid Daleel.

I will also try to highlight different analytical aspects of the Hadiths, practices of the Ummah for the last 1400 years, the saying and verdicts of the Salaf and answers to some of the arguments which are put forward by the other side.

So in this post you will see the Daleel and that Taraweeh and Tahajjud are two seperate prayers.

The hadith on 20 Rakaat narrated by Abu Usman Al Basri(R) has been attested by Imam Bayhaqi(R) at another place.

Reference: Mu'arif As Sunan

Imam Bayhaqi(R) considers Abu Usman Al Basri(R) Siqah (Trustworthy) and thats is why he has approved and attested this hadith as Sahih.

Reference: Mu'arif As-Sunan Wal Aasaar Book 3, Page 15