Salam alaikum.

Kulayni narrated in Kafi vol 1, p 223, #1:

ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنْ عَبْدِ الْعَزِيزِ بْنِ الْمُهْتَدِي عَنْ عَبْدِ الله بْنِ جُنْدَبٍ أَنَّهُ كَتَبَ إِلَيْهِ الرِّضَا (عَلَيْهِ السَّلام) أَمَّا بَعْدُ فَإِنَّ مُحَمَّداً (صَلَّى اللهُ عَلَيْهِ وَآلِه) كَانَ أَمِينَ الله فِي خَلْقِهِ فَلَمَّا قُبِضَ (صَلَّى اللهُ عَلَيْهِ وَآلِه) كُنَّا أَهْلَ الْبَيْتِ وَرَثَتَهُ فَنَحْنُ أُمَنَاءُ الله فِي أَرْضِهِ عِنْدَنَا عِلْمُ الْبَلايَا وَالْمَنَايَا وَأَنْسَابُ الْعَرَبِ وَمَوْلِدُ الاسْلامِ وَإِنَّا لَنَعْرِفُ الرَّجُلَ إِذَا رَأَيْنَاهُ بِحَقِيقَةِ الايمَانِ وَحَقِيقَةِ النِّفَاقِ وَإِنَّ شِيعَتَنَا لَمَكْتُوبُونَ بِأَسْمَائِهِمْ وَأَسْمَاءِ آبَائِهِمْ أَخَذَ الله عَلَيْنَا وَعَلَيْهِمُ الْمِيثَاقَ يَرِدُونَ مَوْرِدَنَا وَيَدْخُلُونَ مَدْخَلَنَا لَيْسَ عَلَى مِلَّةِ الاسْلامِ غَيْرُنَا وَغَيْرُهُمْ نَحْنُ النُّجَبَاءُ النُّجَاةُ وَنَحْنُ أَفْرَاطُ الانْبِيَاءِ وَنَحْنُ أَبْنَاءُ الاوْصِيَاءِ وَنَحْنُ الْمَخْصُوصُونَ فِي كِتَابِ الله عَزَّ وَجَلَّ وَنَحْنُ أَوْلَى النَّاسِ بِكِتَابِ الله وَنَحْنُ أَوْلَى النَّاسِ بِرَسُولِ الله (صَلَّى اللهُ عَلَيْهِ وَآلِه) وَنَحْنُ الَّذِينَ شَرَعَ الله لَنَا دِينَهُ فَقَالَ فِي كِتَابِهِ شَرَعَ لَكُمْ يَا آلَ مُحَمَّدٍ مِنَ الدِّينِ ما وَصَّى بِهِ نُوحاً قَدْ وَصَّانَا بِمَا وَصَّى بِهِ نُوحاً وَالَّذِي أَوْحَيْنا إِلَيْكَ يَا مُحَمَّدُ وَما وَصَّيْنا بِهِ إِبْراهِيمَ وَمُوسى‏ وَعِيسى‏ فَقَدْ عَلَّمَنَا وَبَلَّغَنَا عِلْمَ مَا عَلِمْنَا وَاسْتَوْدَعَنَا عِلْمَهُمْ نَحْنُ وَرَثَةُ أُولِي الْعَزْمِ مِنَ الرُّسُلِ أَنْ أَقِيمُوا الدِّينَ يَا آلَ مُحَمَّدٍ وَلا تَتَفَرَّقُوا فِيهِ وَكُونُوا عَلَى جَمَاعَةٍ كَبُرَ عَلَى الْمُشْرِكِينَ مَنْ أَشْرَكَ بِوَلايَةِ عَلِيٍّ ما تَدْعُوهُمْ إِلَيْهِ مِنْ وَلايَةِ عَلِيٍّ إِنَّ الله يَا مُحَمَّدُ يَهْدِي إِلَيْهِ مَنْ يُنِيبُ مَنْ يُجِيبُكَ إِلَى وَلايَةِ عَلِيٍّ (عَلَيْهِ السَّلام).

1. Ali ibn Ibrahim has narrated from his father from ‘Abd al-‘Aziz ibn al-Muhtadi from ‘Adallah ibn Jundab to who Imam al-Rida (a.s.) wrote the following. “Thereafter, (thanking Allah) Muhammad (s.a.) was the trustee of Allah for His creatures. When he was taken away from this world we, Ahl al-Bayt inherited him, thus, we are the trustees of Allah over His earth. With us is the knowledge of the sufferings, the death, the genealogy of the Arabs and the birth of Islam. We know the man when we see him in the truth of faith or hypocrisy. Our followers (Shi‘a) are listed (with us) by their names and the names of their fathers. Allah has established a covenant with them and with us. They land wherever we would do so and enter wherever we would enter. There is no one besides us and them upon Islamic nation. We are the noble saviors and the descendents of the prophets and of the children of the successors of the prophets. We the ones to whom the book of Allah, the Most Holy, the Most High, has come exclusively. We, of all people, have the first priority (closeness) to the book of Allah. We, of all people, have the first priority (closeness) to the Messenger of Allah. For us He formed His religion.

“He has established for you (family of Muhammad) a form of religion which is of the commands to Noah {we are commanded with whatever Noah was commanded}. It is of the mattes that We have revealed to you (Muhammad) and of the commands to Noah, Abraham, Moses, and Jesus to follow.{We have taught and preached the knowledge that was taught to us. We were given the knowledge of these prophets. We are the heirs of the commissioned Messengers}. (He has explained it) so that you (family of Muhammad) would be steadfast and united (all in a united group) in your religion. What you call the polytheists {polytheists in the acknowledgement of the Divine authority of Imam Ali (a.s.} to{the acknowledgement of the Divine authority of Imam Ali (a.s.}is extremely grave for them. God {O Muhammad} attracts to (the religion) whomever He wants and guides to it whoever turns to Him in repentance.” (42:13)

Majlisi in “Mirat” said hadith is hasan (good).

So dear Muslim don’t be deluded by their false call to so called Islamic unity, they don’t see anyone except themselves upon Islam.