Ali's enemy is the enemy of Allah

بسم الله الواحد القهار

Sheikh Al-Mufid:

He said: Abu Ja'far Mohammad Ibn Ali Ibn al-Husain reported to me from his father, who reported from Mohammad Ibn Yahya Al-Attaar, who reported from Ahmad Ibn Mohammad Ibn Isa, from Ali Ibn Al-Hakam, from Hisham Ibn Salim, from Sulayman Ibn Khalid, from Abu Abdillah Ja'far Ibn Muhammad al-Sadiq(عليه السلام), from his forefathers(عليهم السلام), who said:
The Prophet(صلى الله عليه وآله وسلم), told Ali(عليه السلام):
"O Ali, you are from me and I from you. Your friend is my friend and my friend is Allah's friend. 
And your enemy is my enemy and my enemy is the enemy of Allah. 
O Ali, I am at war with the one who fights you and at peace with one who is at peace with you. 
O Ali, you have a treasure in the Heaven and you are the master of its both sides. 
O Ali, you are the divider of heaven and hell. 
None shall enter the heaven unless he has recognized you, and you have recognized him! 
And none shall enter hell unless he has rejected you and you have rejected him. 
O Ali, you and your descendants shall be on the heights (al-A'araaf) on the Day of Judgment, recognizing the sinners by their marks, and the believers by their signs. 
O Ali, the believers would not have been distinguished, after I have departed, if you were not there."

Source: Amali Al-Mufid, Assembly 24, H-No. 4, Pg. 213

Grading: Sahih(authentic), its narrators are trustworthy.

Check the Rijaal section for the authenticity of the Chain:

1727: Mohammad Ibn Ali Ibn Al-Husain Ibn Babawaih Al-Qummi
1231: Ali Ibn Al-Husain Ibn Musa Ibn Babawaih(father of Sheikh As-Saduq)
1819,1820: Mohammad Ibn Yahya Al-Attaar Al-Qummi
130: Ahmad Ibn Mohammad Ibn Isa Ibn Abdullah Al-Ash'ari Al-Qummi
1235: Ali Ibn Al-Hakam Al-Anbari, Al-Kufi, An-Nakha'ee
2040: Hisham Ibn Salim Al-Jawaliqi
842: Sulayman Ibn Khalid Al-Aqta'