Hadith 31-217

وَبِإِسْنادِهِ قالَ: قالَ رَسُولَ اللَّهِ‏ صَلَّى اللهُ عَلَيْهِ وَآلِهِ: الأَئِمَّةُ مِن وُلْدِ الحُسَيْن، مَن أَطاعَهُم أَطاعَ اللَّه، وَمَن عَصاهُم فَقَدْ عَصَى اللَّه عَزَّ وَجَلَّ، هُمُ العُرْوَةُ الوُثْقى‏، وَهُمُ الوَسيلَةُ إِلَى اللَّهِ عَزَّ وَجَلَّ.

According to the same documentation, God’s Prophet (S) said, “The Imams are from the progeny of Al-Husayn (a.s.). Whoever obeys them it is as if he has obeyed God, and whoever disobeys them it is as if he has disobeyed the Honorable the Exalted God. They are a Reliable Grip and a means towards God.”