The narrations referring to the twelve Imam's (as) can be found in the following different formats:

• • Total of 12 Imam's (as) as successors after Prophet Muhammad (saww)

  • 14 lights created by Allah (swt). This includes Prophet Muhammad (saww), Fatema Zehra (sa) and then the 12 Imam's (as).

  • 11 Imam's (as) as the descendant of Prophet Muhammad (saww) - This would refer to taking descendants of Imam Ali (as)  as descendants of Prophet Muhammad (saww).

  • 9 Imam's (as) from the descendants of Imam Husain (as) .

  • 5th Imam (as) from the descendants of Imam Musa Kazim will be Qaim (atfs).

Below are few of these narrations collected here

~From the Quran~

There are 3 verses in the Holy Quran along with narrations from Prophet Muhammad (saww) and the Imam's (as) which proof that the number of Imam's (as) appointed by Allah (swt) will be twelve. 

وَلَقَدْ أَخَذَ اللَّهُ مِيثَاقَ بَنِي إِسْرَائِيلَ وَبَعَثْنَا مِنْهُمُ اثْنَيْ عَشَرَ نَقِيبًا

"Allah did take a covenant from the Children of Israel, and we appointed twelve captains among them..." [5:12]

إِنَّ عِدَّةَ الشُّهُورِ عِندَ اللَّهِ اثْنَا عَشَرَ شَهْرًا فِي كِتَابِ اللَّهِ

"Verily the number of Months near (in sight of) Allah (swt) are twelve in the book of Allah (swt).." [9:36]

وَإِذِ اسْتَسْقَىٰ مُوسَىٰ لِقَوْمِهِ فَقُلْنَا اضْرِب بِّعَصَاكَ الْحَجَرَ فَانفَجَرَتْ مِنْهُ اثْنَتَا عَشْرَةَ عَيْنًا

"And when Moses prayed for water for his people; We said: "Strike the rock with thy staff." Then gushed forth therefrom twelve springs..." [2:60]

عن ابن عباس قال: سمعت رسول الله صلّى الله عليه وآله يقول: معاشر المسلمين اعلموا انّ لله تعالى باباً مَن دخلها أمن من النار ومن الفزع الأكبر، فقام إليه أبو سعيد الخدري فقال: يا رسول الله إهدنا إلى هذا الباب حتّى نعرفه

قال: هو عليّ بن أبي طالب سيّد الوصيّين، وأمير المؤمنين، وأخو رسول ربّ العالمين، وخليفته على الخلق أجمعين، معاشر الناس من أحبّ أن يستمسك بالعروة الوثقى التي لا انفصام لها فليستمسك بولاية عليّ بن أبي طالب، فإنّ ولايته ولايتي، وطاعته طاعتي، معاشر الناس من أحبّ أن يعرف الحجّة بعدي فليعرف عليّ بن أبي طالب عليه السلام، معاشر الناس من سرّه أن يتوالى بولاية الله فليتقلّد  بعليّ بن أبي طالب عليه السلام فإنّه خزانة علمي، [معاشر الناس من أحبّ أن يلقى الله وهو عنه راض فليوال عدّة الأئمة]

فقام جابر بن عبد الله فقال: وما عدّة الأئمة؟ فقال: يا جابر سألتني ـ يرحمك الله ـ عن الإسلام بأجمعه، عدّتهم عدّة الشهور وهي عند الله اثني عشر شهراً في كتاب الله يوم خلق السماوات والأرض، وعدّتهم عدّة العيون التي انفجرت لموسى بن عمران عليه السلام حين ضرب بعصاه البحر فانفجرت منه اثنتا عشرة عيناً، وعدّتهم عدّة نقباء بني اسرائيل. قال الله تعالى: {ولقد أخذ الله ميثاق بني اسرائيل وبعثنا منهم اثني عشر نقيباً}، والأئمة يا جابر اثنا عشر، أوّلهم عليّ بن أبي طالب وآخرهم القائم صلوات الله عليهم أجمعين

From Ibn Abbas who said, I heard Prophet Muhammad (saww) say, "O the Muslim community, know that for Allah (swt) there is a door, whoever enters it, is save from the fire and from the greatest fear."

Then Abu Saeed Al-Khudhri stood up and said, "O Messenger of Allah (swt), Guide us towards this door such that we know it."

Prophet Muhammad (saww) said, "He is Ali ibn Abi Talib (as), the Master of the Guardians and Amir Al-Momineen and the brother of the Messenger of Allah (swt), and His successor over all the creations."

"O People, the one who wishes that he holds on to the strong rope which does not break/separate, then he should hold on-to the Wilayah of Ali bin Abi Talib (as). Because His Wilayah is My Wilayah, and his obedience is My obedience."

"O People, the one who wishes that he recognizes the Hujjah (proof) after Me, then he should recognize Ali bin Abi Talib (as)."

"O People, the one who is pleased that he befriends the Wilayah of Allah (swt), then he should Hold on to Ali ibn Abi Talib (as), because He is keeper of My knowledge."

"O People, the one who wishes that he meets Allah (swt) while Allah (swt) is pleased with him, Then he should believe in Wilayah of number of Imam’s (as)."

Then Jabin bin Abdullah stood up and said, “And what is the Number of the Imam’s (as)?”

Prophet Muhammad (saww) said, “O Jabir, You asked me, Allah (swt) have mercy upon you. For Islam with its entirety, the number of Imam’s (as) is the number of months and this is near (in sight of) Allah (swt) twelve months in the book of Allah (swt) on the day of the creation of the skies and the earth. [9:36]

And the number of the Imam’s (as) is the number of springs that gushed forth for Musa bin Imran (as) when He struck the sea with his staff and gushed forth from it twelve springs. [2:60] And the number of the Imam’s (as) is the number of chiefs of Bani Israeel. Allah (swt) says, "Allah did take a covenant from the Children of Israel, and we appointed twelve chiefs among them.” [5:12]. And the Imam’s (as) O Jabir, the first of them is Ali bin Abi Talib (as) and the last of them is Al-Qaim (atfs), blessings be upon them all.

[Source: Irshaad Al-Quloob, Vol. 2, Pg. 261]

النبي ( ص : ) كائن في امتي ما كان في بني اسرائيل حذو النعل بالنعل والقذة بالقذة ، كان فيهم اثنا عشر نقيبا قوله ( وبعثا منهم اثنى عشر نقيبا )

From Prophet Muhammad (saww), "Will happen in my ummah like what was in bani israeel..... And among them were twelve chiefs. Allah (swt) has said, "And we appointed twelve chiefs among them.." [5:12]

[Source: Al-Manaqib - Ibn Shahr Ashoob, Vol. 1, Pg. 300]

وَالْفَجْرِ وَلَيَالٍ عَشْرٍ

"By the Day Break. And by the ten nights" [89:1-2]

ما روي بالاسناد مرفوعا، عن عمرو بن شمر، عن جابر بن يزيد الجعفي عن أبي عبدالله عليه السلام قال: قوله عزوجل (والفجر هو القائم عليه السلام وليال عشر الائمة عليهم السلام من الحسن إلى الحسن والشفع أمير المؤمنين وفاطمة عليهما السلام والوتر هو الله وحده لا شريك له

Narrated (disconnectedly) from Umroo bin Shimr, from Jabir bin Yazid Al-Jofi, from Abi Abdillah (as) who said:

Regarding the saying of Allah (swt), "Al-Fajr, It is the Al-Qaim (as). And the ten nights are the Imam's (as) from Al-Hasan (as) to Al-Hasan (as)*. And Al-Shaf is Amir Al-Momineen (as) and Fatema (sa) and Al-Witr is Allah (swt) the Single, there is no partner with Him."

* This refers to the 10 Imam's (as) from the second Imam Al-Hasan bin Ali (as) to the eleventh Imam Al-Hasan Al-Mujtaba (as).

[Source: Taweel Al-Aayat, Vol. 2, Pg. 792]

~From the Ahadees~

There are numerous narrations in various book of Ahadees which state clearly that there will be 12 Imam's (as) after Prophet Muhammad (saww). 

Apart from those narration here are the narrations from Asl of Abi Saeed Gabbad Al-Asfeeri * proving that there would be 12 Imam's (as) after the Prophet Muhammad (saww) and the 12th would be the Qaim (atfs)

* This is one of the 16 usool that have reached us. The book can be seen in here: http://rafed.net/booklib/view.php?type=c_fbook&b_id=552

Hadith 1:

عباد عن عمرو عن ابى حمزه قال سمعت على بن الحسين (ع) يقول ان الله خلق محمدا وعليا واحد عشر من ولده من نور عظمته فاقامهم اشباحا في ضياء نوره يعبدونه قبل خلق الخلق يسبحون الله ويقدسونه وهم الائمة من ولد رسول الله

Narrated that Imam Ali ibn husayn (عليه السلام) said,

"Allah created Muhammad (صلى الله عليه وآله), Ali (عليه السلام) and the eleven Imams from his descendants out of the light (noor) of His greatness. He then placed them as figures in the brightness of His light where they worshipped Him before the creation of the creations. They would speak of the Glory of Allah and of His Holiness. They are the Imams from descendants of the Messenger of Allah (صلى الله عليه وآله)."

This narration also comes up later in Al-Kafi with the following chain:

مُحَمَّدُ بْنُ يَحْيَى عَنْ مُحَمَّدِ بْنِ أَحْمَدَ عَنْ مُحَمَّدِ بْنِ الْحُسَيْنِ عَنْ أَبِي سَعِيدٍ الْعُصْفُرِيِّ عَنْ عَمْرِو بْنِ ثَابِتٍ عَنْ أَبِي حَمْزَة

Hadith 2:

عباد رفعه إلى ابى جعفر (ع) قال قال رسول الله (ص) من ولدي احد عشر نقيبا نجيبا ( نقباء نجباء خ د ) محدثون مفهمون اخرهم القائم بالحق يملاءها ( الارض خ د ) عدلا كما ملئت جورا

Abbad (disconnected) from Abi Jafar (as) who said Prophet Muhammad (saww) said,

"From my progeny will be eleven* leaders, successors, those who narrate and explain. The last of them is Al-Qaim with the truth, He will fill the earth with justice, like how it was filled with injustice."

* Eleven - excluding Imam Ali (as). Sons of Imam Ali (as) referred to as the sons of Prophet Muhammad (as).

Hadith 3:

عباد عن عمرو بن ثابت عن ابي جعفر عن ابيه عن ابائه قال قال رسول الله صلى الله عليه وعليهم نجوم في السماء امان لاهل السماء فإذا ذهب نجوم السماء اتى اهل السماء ما يكرهون ونجوم من اهل بيتي من ولدي احد عشر نجما امان في الارض لاهل الارض ان تميد باهلها فإذا ذهبت نجوم اهل بيتي من الارض اتى اهل الارض ما يكرهون

Abbad bin Umroo bin Saabit, from Abi Jafar (as), from His Father (as), from His Fathers (as), who said:

Messenger of Allah (swt) said, "Stars in the sky are (source of) safety for the inhabitants of the sky. So if the stars of the sky were to go, there would come upon the the inhabitants of the sky what they dislike. And the stars from my AhlulBait (as) from my Loins are 11 starts, (source of) safety in the earth for the inhabitants of the earth from it shaking along with its inhabitants. So if the starts of My AhlulBait (as) were to go from the earth, there would come upon the inhabitants of the earth what they dislike."

Following narrations are from later sources such as Al-Kafi:

Hadith 4:

عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ سَعِيدِ بْنِ غَزْوَانَ عَنْ أَبِي بَصِيرٍ عَنْ أَبِي جَعْفَرٍ ع قَالَ يَكُونُ تِسْعَةُ أَئِمَّةٍ بَعْدَ الْحُسَيْنِ بْنِ عَلِيٍّ تَاسِعُهُمْ قَائِمُهُم‏

Narrated Ali bin Ibrahim, from his father, from Ibn Abi Umayr, from Saeed bin Guzwan, from Abi Baseer, from Abi Jafar (as):

Abi Jafar (as) said, "There will be nine Imam's (as) after Al-Husain bin Ali (as). The ninth of them will be the Qaim (atfs).

[Source: Al-Kafi, Vol. 1, Pg. 533]

All narrators are trustworthy, Hadees is Saheeh (Authentic)

Hadith 5:

وَ بِهَذَا الْإِسْنَادِ قَالَ قَالَ رَسُولُ اللَّهِ ص لِأَصْحَابِهِ آمِنُوا بِلَيْلَةِ الْقَدْرِ إِنَّهَا تَكُونُ لِعَلِيِّ بْنِ أَبِي طَالِبٍ وَ لِوُلْدِهِ الْأَحَدَ عَشَرَ مِنْ بَعْدِي‏

And with the previous chain, narrated from the Messenger of Allah (saww):

The Messenger of Allah (saww) said to his companions, "Believe in the night of Qadr, because it was for Ali bin Abi Talib (as) and for his 11 son after Me."

[Source: Al-Kafi, Vol. 1, Pg. 533]

Hadith 6:

أَبُو عَلِيٍّ الْأَشْعَرِيُّ عَنِ الْحَسَنِ بْنِ عُبَيْدِ اللَّهِ عَنِ الْحَسَنِ بْنِ مُوسَى الْخَشَّابِ عَنْ عَلِيِّ بْنِ سَمَاعَةَ عَنْ عَلِيِّ بْنِ الْحَسَنِ بْنِ رِبَاطٍ عَنِ ابْنِ أُذَيْنَةَ عَنْ زُرَارَةَ قَالَ سَمِعْتُ أَبَا جَعْفَرٍ ع يَقُولُ الِاثْنَا عَشَرَ الْإِمَامَ مِنْ آلِ مُحَمَّدٍ كُلُّهُمْ مُحَدَّثٌ مِنْ وُلْدِ رَسُولِ اللَّهِ ص وَ وُلْدِ عَلِيِّ بْنِ أَبِي طَالِبٍ ع فَرَسُولُ اللَّهِ ص وَ عَلِيٌّ ع هُمَا الْوَالِدَان‏

Abi Ali Al-Ashari, from Al-Hasan bin Ubaid Allah, from Al-Hasan bin Mooosa Al-Khashaab, from Ali bin Sama'at, from Ali bin Al-Husain bin Ribat, from Ibn Uzainah, from Zurarah who said I heard Aba Jafar (as) saying:

"There will be twelve Imams from the family of Muhammad (as) and they all will be (Muhaddasun), persons to whom angles speak. They will be of the descendants of the Messenger of Allah and Ali ibn abu Talib (as). The Messenger of Allah (saww) and Ali (as) are the two fathers."

[Source: Al-Kafi, Vol. 1, Pg. 533]

Note: There could be an objection on this narration that, if twelve Imam's (as) are descendants of Prophet Muhammad (saww) then how come Imam Ali (as) is also part of it?? This is in-fact explained in the last part of the narration itself where in its clearly stated that both Prophet Muhammad (saww) and Imam Ali (as) are the two fathers. And as per another narration Prophet Muhammad (saww) is also a father of Imam Ali (as) in this very sense. Read the narration here.

Hadith 7:

الْحُسَيْنُ بْنُ مُحَمَّدٍ عَنْ مُعَلَّى بْنِ مُحَمَّدٍ عَنِ الْوَشَّاءِ عَنْ أَبَانٍ عَنْ زُرَارَةَ قَالَ سَمِعْتُ أَبَا جَعْفَرٍ ع يَقُولُ نَحْنُ اثْنَا عَشَرَ إِمَاماً مِنْهُمْ حَسَنٌ وَ حُسَيْنٌ ثُمَّ الْأَئِمَّةُ مِنْ وُلْدِ الْحُسَيْن‏

Al-Husain bin Muhammad, from Mualla bin Muhammad, from Al-Washa, from Aban, from Zurarah who said I heard:

Aba Jafar (as) said, "We are twelve Imam's (as). From them is Hasan (as) and Husain (as), then the Imam's (as) from the descendants of Husain (as)."

[Source: Al-Kafi, Vol. 1, Pg. 533]

Hadith 8:

قال حدثنا أبو جعفر محمد بن علي بن الحسين قال حدثني أبي قال حدثنا سعد بن عبد الله عن محمد بن الحسين بن أبي الخطاب عن محمد بن سنان عن المفضل بن عمر الجعفي عن جابر بن يزيد عن أبي جعفر محمد بن علي بن الحسين عن أبيه عن جده ع قال قال رسول الله ص لعلي بن أبي طالب ع يا علي أنا و أنت و ابناك الحسن و الحسين و تسعة من ولد الحسين أركان الدين و دعائم الإسلام من تبعنا نجا و من تخلف عنا فإلى النار

Narrated to us Abu Jafar Muhammad bin Ali bin Al-Husain, from his father, from Saad bin Abdullah, from Muhammad bin Al-Husain bin Abi Al-Khattab, from Muhammad bin Sinaan, from Al-Mufazzal bin Amr Al-Jofi, from Jabir bin Yazeed from Abi Jafar Muhammad bin Ali bin Al-Husain (as), from His father, from His fathers who said:

Messenger of Allah (swt) said to Ali bin Abi Talib (as), "O Ali, I and You and your sons Al-Hasan (as) and Al-Husain (as) and nine from the sons of Al-Husain (as) are the pillars of religions and pillars of Islam. Who obeys Us will succeed and who leaves Us will be towards the fire."

[Source: Al-Amali, Sheikh Mufeed, Pg. 217]