Hadith 1:

حدثنا محمد بن الحسن رضي الله عنه قال: حدثنا سعد بن عبد الله، عن أحمد بن محمد بن عيسى، عن القاسم بن الحسن بن علي بن يقطين، عن ابن أبي نجران، و جعفر بن سليمان، عن العلاء بن رزين، عن أبي حمزة الثمالي قال: قال أبو جعفر عليه السلام: بني الاسلام على خمس: إقام الصلاة، وإيتاء الزكاة، وحج البيت، وصوم شهر رمضان والولاية لنا أهل البيت، فجعل في أربع منها رخصة، ولم يجعل في الولاية رخصة من لم يكن له مال لم يكن عليه الزكاة، ومن لم يكن عنده مال فليس عليه حج، ومن كان مريضا صلى قاعدا وأفطر شهر رمضان. والولاية صحيحا كان أو مريضا أو ذا مال أو لا مال له فهي لازمة [واجبة]

Narrated that Abu Jafar Imam Baqir (عليه السلام) said,

"Islam is built upon five pillars: Establishing prayers (salat), giving Zakat, performing Hajj to the House, fasting during the month of Ramadan, and guardianship/mastership (Wilayah) to Us - the AhlulBayt (عليهم السلام).

Thus, He made exemptions/concession in four of them but did not make any exemption in Mastership (Wilayah). So, whoever has no wealth, Zakat is not obligatory upon him; whoever has no wealth, Hajj is not obligatory upon him; whoever is sick, he prays sitting down and breaks his fast during the month of Ramadan (i.e. does not fast), and regarding Mastership (Wilayah) - whether one is healthy or sick, is wealthy or not - it is obligatory."

[Source: al-Khisal, Shaikh Sadooq, Pg. 277]

Hadith 2:

Narrated that Imam Sadiq (عليه السلام) said as part of a narration:

لَوْ أَنَّ إِبْلِيسَ سَجَدَ لِلَّهِ عَزَّ ذِكْرُهُ بَعْدَ الْمَعْصِيَةِ وَ التَّكَبُّرِ عُمُرَ الدُّنْيَا مَا نَفَعَهُ ذَلِكَ وَ لَا قَبِلَهُ اللَّهُ عَزَّ ذِكْرُهُ مَا لَمْ يَسْجُدْ لآِدَمَ كَمَا أَمَرَهُ اللَّهُ عَزَّ وَ جَلَّ أَنْ يَسْجُدَ لَهُ وَ كَذَلِكَ هَذِهِ الْأُمَّةُ الْعَاصِيَةُ الْمَفْتُونَةُ بَعْدَ نَبِيِّهَا (صلى الله عليه وآله) وَ بَعْدَ تَرْكِ هِمُ الْإِمَامَ الَّذِي نَصَبَهُ نَبِيُّهُمْ (صلى الله عليه وآله) لَهُمْ فَلَنْ يَقْبَلَ اللَّهُ تَبَارَكَ وَ تَعَالَى لَهُمْ عَمَلًا وَ لَنْ يَرْفَعَ لَهُمْ حَسَنَةً حَتَّى يَأْتُوا اللَّهَ عَزَّ وَ جَلَّ مِنْ حَيْثُ أَمَرَهُمْ وَ يَتَوَلَّوُا الْإِمَامَ الَّذِي أُمِرُوا بِوَلَايَتِهِ وَ يَدْخُلُوا مِنَ الْبَابِ الَّذِي فَتَحَهُ اللَّهُ عَزَّ وَ جَلَّ وَ رَسُولُهُ لَهُمْ يَا أَبَا مُحَمَّدٍ إِنَّ اللَّهَ افْتَرَضَ عَلَى أُمَّةِ مُحَمَّدٍ (صلى الله عليه وآله) خَمْسَ فَرَائِضَ الصَّلَاةَ وَ الزَّكَاةَ وَ الصِّيَامَ وَ الْحَجَّ وَ وَلَايَتَنَا فَرَخَّصَ لَهُمْ فِي أَشْيَاءَ مِنَ الْفَرَائِضِ الْأَرْبَعَةِ وَ لَمْ يُرَخِّصْ لِأَحَدٍ مِنَ الْمُسْلِمِينَ فِي تَرْكِ وَلَايَتِنَا لَا وَ اللَّهِ مَا فِيهَا رُخْصَةٌ

"If Iblis (Satan) were to prostrate to Allah (عز ذكره) after his act of disobedience and arrogance for the entire duration of this world, it would not benefit him, nor would Allah accept it from him, as long as he did not prostrate to Adam as Allah (عز وجل) had commanded him to do.

Likewise is this disobedient and misguided Ummah (community) after [the passing of] its Prophet (صلى الله عليه وآله) and after their abandoning/leaving the Imam whom their Prophet had appointed for them. Allah (تبارك وتعالى) will never accept any deed from them, nor will He elevate any good work of theirs, until they come to Allah (عز وجل) from the path He commanded them and accept the authority (Wilayah) of the Imam they were commanded to follow, and enter through the gate that Allah and His Messenger opened for them.

O Abu Muhammad, indeed Allah made five obligations necessary upon the Ummah of Muhammad (صلى الله عليه وآله): Prayer (Salah), Almsgiving (Zakat), Fasting (Sawm), Pilgrimage (Hajj), and our Wilayah [Mastership]. He granted them concessions (exemptions) in certain aspects of the [first] four obligations, but He did not grant any Muslim a concession to abandon our Wilayah. No, by Allah, there is no concession regarding it."

[Source: al-Kafi, Vol. 8, Hadith. 399]