The Imams are the corner stone on earth

“Whatever Ali (a.s.) has brought I follow them entirely and whatever he has forbidden I desist from them altogether. It flows for him from the merits like what flowed for Muhammad (sw), and for Muhammad (sw) is the merit upon the entirety of the creatures of Allah, the Mighty and Majestic. The pursuer upon him (Imam Ali) regarding something from his decisions is like the pursuer upon Allah and upon His Messenger, and the rejecter upon him regarding a small or a big (matter), would be within the limits of Shirk (Association) with Allah.
Amir al-Mu’minin (a.s.) was the gate to Allah through which one could only go closer to Him, and he was the path that if one would ignore it he would have been destroyed. This is also true of all the Imams of guidance, one after the other. Allah has made them as the cornerstones of the earth so that its inhabitants would not be destroyed, and His possessors of doubtless Divine authority over the inhabitants of earth and those below the earth. Amir al-Mu’minin (a.s.) would very often say, “I am Allah's distributor between Paradise and Hellfire, and I am the greatest criterion, and I am the possessor of the Staff and the (marking) seal Miysam. All the angels, the Spirit, and the messengers have acknowledged me, like what they acknowledged Muhammad (sw) with, and I am loaded upon like his load, and it is the load of the Lord.
The Messenger of Allah (sw) will be called upon and his call will be accepted. I will be called up on and my call will be accepted. He will be made to speak and I will be made to speak and I will speak just the way he would speak. I have been given certain distinctions which were not given to anyone before me. I was taught all about the deaths, the sufferings, the genealogy of people and the decisive sermons. I have not missed any of the knowledge that have passed me by and nothing of the future is unseen or unknown to me. I give good news by the permission of Allah and do my duty towards Allah. All of this is from Allah Who has made it possible for me through His knowledge.”
Al-Husayn ibn Muhammad al-Ash‘ari has narrated from Mu‘alla ibn Muhammad from Muhammad ibn Jumhur al-‘Ammi from Muhammad ibn Sinan who has said that al-Mufaddal narrated to us from abu ‘Abdallah (a.s.). He then narrated the above Hadith.

"I entered, along with Sulayman ibn Khalid, upon Abu Abdillah (as). He started speaking to us, saying:
'O Sulayman, what comes from Amir al-Mu'minin (as) is to be adhered to, and what he prohibits is to be avoided. He has been given the same virtue that was given to the Messenger of Allah (sw), and the Messenger of Allah (sw) has a virtue over all of God’s creation. Whoever finds fault with Amir al-Mu'minin (as) in any of his rulings is like one who finds fault with Allah Almighty and His Messenger (sw). Rejecting him in small or large matters is akin to associating others with Allah. Amir al-Mu'minin (as) was the gate of Allah, which no one could enter except through him, and the path of Allah, which whoever treads otherwise will be destroyed. This is the way the Imams (as) continued, one after another. Allah made them the pillars of the earth, so that it would not shake with its inhabitants, and the irrefutable proof over those above the earth and beneath the soil.'
He also said: 'Amir al-Mu'minin (as) said: "I am the divider by Allah's command between Paradise and Hell. I am the Greater Faruq (the distinguisher between truth and falsehood). I am the bearer of the staff and the (marking) seal. All the angels and the spirit have acknowledged my station, just as they acknowledged Muhammad (sw). I have been made to carry a similar burden as that of Muhammad (sw), which is the burden from the Lord. Indeed, Muhammad (sw) will be called and clothed and made to speak, and I will be called and clothed and made to speak, and I will speak just as he speaks. I have been given qualities that no one before me was given: I have been taught the knowledge of death, calamities, genealogies, and the ability to judge decisively. Nothing from the past escapes me, and nothing from the future is hidden from me. By the permission of Allah, I give glad tidings, and I deliver on behalf of Allah, the Almighty. All of this was granted to me by Allah's permission."'

“A merit of Amir al-Mu'mineen (a.s.) is that whatever he has brought, I follow it entirely, and whatever he has forbidden, I desist from it altogether. It flows for him from the obedience after the Messenger of Allah (sw), what flowed for the Messenger of Allah (sw), and the merit is for Muhammad (sw). The one who tries to be ahead of him would be considered as trying to be ahead of Allah and his Messenger. And the one who tries to show himself as more virtuous than him would be considered as trying to show himself as more virtuous than the Messenger of Allah (sw). And the rejector upon him regarding a small or big (matter) would be within the limits of shirk to Allah.
The Messenger of Allah (sw) is a Door of Allah which one cannot come to Him except from it, and His Way which the one who travels it arrives to Allah, the Mighty and Majestic. The same was true of Ami al-Mu'mineen (a.s.) after him (Muhammad), and it flowed for the Imams (peace be upon them), one after one. Allah, the Mighty and Majestic, has made them the cornerstone of the earth so that its inhabitants would not be destroyed, and they were the pillars of Islam and the connection in the path of guidance. No guide can be a guide except their guidance, nor would one stray outside from the guidance except by being deficient in their rights.
They are the trustees of Allah over whatever knowledge, warning, and excuses that have been revealed to them. They possess the doubtless Divine authority over those on earth. It flows for the last of them from Allah similar to which flowed for their first one, and no one would arrive to that except by the Assistance of Allah. And Amir al-Mu’minin (a.s.) has said, “I am the distributor for Allah between Paradise and Hell. None can enter it except upon a limit of my distribution, and I am the greatest criterion, and the Imam for those after me, and the communicator on behalf of those before me. No one precedes me except Ahmad (sw). I and he are on one path, except that he is the one called by his name.
And I have been given six things: the knowledge of deaths, that of the tribulations, that of the wills, and decisive sermons, and I am the owner of the spheres and a state of the states, and I am the owner of the Staff and the Branding iron, and the Beast (27:82) who would be speaking to the people."