Tafsir of Al-Fath 48:22

"And if those who disbelieved had fought you"—meaning the people of Mecca, had they not reconciled with you, as narrated by Qatadah. Ibn al-Mundhir recorded from Ibn Jurayj that they were the allies of the people of Khaybar, the tribes of Asad and Ghatafan. It is also said that they were the Jews, but that is not strong.

"they would have turned their backs"—meaning they would have been defeated; turning the back is a metonym for defeat.

"and then they would not have found a protector"—to guard them. Al-Khafaji mentioned that "guard" is one of the meanings of wali (protector/ally), and its interpretation here as such is appropriate for the one who is defeated. Al-Raghib stated: Everyone who takes charge of another’s affair is his wali. Accordingly, a guard is a wali because he manages the affairs of the protected one. The use of the indefinite form is for generalization, meaning they would not find any individual whatsoever among the protectors.

"nor a helper"—nor any individual whatsoever among the helpers to assist them. The Imam said: The intended meaning of wali is one who benefits through gentleness, and nasir (helper) is one who benefits through force.