Faiz bin Mihtar, from his father, from Mohammad bin Ali Al-Baqir (A.s.), from his father (4th Imam (A.s.), from his grandfather (3rd Imam(a.s.)) who said:
The MESSENGER OF ALLAH (SWT) was riding (a horse/mule) and ALI BIN ABI TALEB (ASWS) was walking beside him.
The PROPHET (SAWW) said to him, “O ALI (ASWS)! Either ride or go back because ALLAH (SWT) ordered that you should ride when I ride, walk when I walk, and sit when I sit except when there is a rule from among the rules of ALLAH (SWT) that needs to be obeyed.
ALLAH (SWT) has not honoured me with anything without honouring you with something similar.
He chose prophethood for me and He assigned you as my successor, so you will carry out the rules of the prophethood and accomplish its most difficult tasks.
I swear to the One who truly sent me as a prophet that those who deny you do not believe in me. And those who reject you have not testified in me, and those who disbelieve in you do not believe in ALLAH (SWT).
Your grace is from my grace, and my grace is a grace for you, And that is why ALLAH (SWT) says, “Say: ‘In the grace of ALLAH (SWT) and in His mercy-in that let them rejoice, it is better than all that they amass” (10:58)
“Grace of ALLAH (SWT)” (in this verse) is my prophethood. “His mercy” is the Wilayat of ALI BIN ABI TALEB (ASWS).”In that” refers to my prophethood and ALI’s (ASWS) Wilayat. “Let them rejoice” refers to (the rejoicing of) the Shia. “It is better than all that they amass” refers to the enemies of the Shia. And “all that they amass” refers to wealth, children, and pleasures of this life.
O ALI (ASWS) ! I swear to ALLAH (SWT) that you were not created except to worship ALLAH (SWT), to make the religion of ALLAH (SWT) known, and to make the path of guidance clear for those who seek it.
Those who deviate from you have gone astray, and those who are not guided to you and to your Wilayat cannot be guided to ALLAH (SWT).
That is why ALLAH (SWT) says, “Verily, I forgive, again and again, whosoever repents, believes, and does good, and then he is guided” (20:82). “Guided” refers to your Wilayat.
O ALI (ASWS)! ALLAH (SWT) has ordered me to announce your rights as religious obligations on people just like my rights.
(Honouring) your rights is a religious obligation on everyone who believes in me. If it had not been for you, the party of ALLAH (SWT) whold not have been known. It is though you that the enemies of ALLAH (SWT) are known. Those who meet ALLAH (SWT) without your Wilayat meet ALLAH (SWT) without anything.
ALLAH (SWT) reveled to me, “(O MOHAMMAD (SWT)) Deliver what has been sent down to you from your Lord” (5:67).
O ALI (ASWS)! This referes to your Wilayat.“And if you do not do it, then, (it will be as if) you have not delivered His message (at all)” (5:67). If I had not announced the order of ALLAH (SWT) about your Wilayat, the value of all of my deeds would have been nullified.
The value of the deeds of those who meet ALLAH (SWT) without your Wilayat will be nullified.
I do not say anything except ALLAH (SWT)'s words, and what I said about you was sent down from ALLAH (SWT) .
(Ref: Amaali of Sadouq 400, Bihar Al-Anwar 38:105)