This well proven hadith in Sunni school of thought Imam Trimdhi also wrote this hadith ” Ali is from and I am from Ali, He is the WALI (Master) of all believers.”
We can understanmd that The Holy Prophet said Ali is from because Imam Ali is the cousin of Holy Prophet and son in law who was raised in the hands of Holy Prophet but when the Holy Prophet said I am from Ali, this is not a light thing. It clearly means that after the HOly Prophet Imam Ali is the true picture of Prophet Mohammad (pbuh).
Imran bin Hossien narrated:
The Holy Prophet said Ali is from and I am from Ali, He is the WALI (Master) of all believers.
Another Narrator narretes
Habshi bin Janadah Salooli narrated:
I heard from the Holy Prophet saying this: Ali is from me and I am from him. Then I said to Abbi Ishaq, did you hear this from him? He (Abi Ishaq) said yes Ali was there, he told me. And also Israil narrates from Abbi Ishaq and Abbi Ishaq from Bara’a that the Holy Prophet said to Ali you are from me and I am from you.