Tafsir of Al Imran 3:28

"Let not the believers take the disbelievers as allies instead of the believers."

They are forbidden from taking the disbelievers as allies due to kinship between them, friendship prior to Islam, or other reasons through which people befriend and associate with one another. This has been repeated in the Qur’an:

• "And whoever among you takes them as allies, then he is indeed one of them" (Al-Māʾidah: 51).
• "Do not take the Jews and the Christians as allies" (Al-Māʾidah: 51).
• "You will not find a people who believe in Allah..." (Al-Mujādilah: 22).

Love for the sake of Allah and hatred for the sake of Allah is a great gateway and a fundamental principle of faith.

"Instead of the believers" This means that in befriending the believers, you have sufficient scope to avoid befriending the disbelievers, so do not prefer the latter over the former.

"And whoever does that has nothing to do with Allah" Whoever befriends the disbelievers has no share in the guardianship (wilāyah) of Allah; the name of guardianship does not apply to him. It means he is completely stripped of Allah’s guardianship. This is a rational matter, for befriending a guardian and befriending his enemy are mutually exclusive. As the poet said: You love my enemy and then claim that I am your friend? Such foolishness is not far from you.

"Except that you guard yourselves against them, a precaution" Except if you fear something from their side that necessitates caution. It is also read as tuqah. The one who guards is called tuqāh and tuqiyyah, similar to how they say "the prince struck the one struck by him."

He granted them a concession to befriend them if they fear them. The intent of this "befriending" is outward opposition and association, while the heart remains reassured in enmity and hatred, waiting for the obstacle to be removed—like the saying of Jesus (peace be upon him): "Be in the middle and walk on the side."

"And Allah warns you of Himself" Do not expose yourselves to His wrath by befriending His enemies. This is a severe threat.

It is permissible to interpret "guard yourselves" (tattaqū) as carrying the meaning of "to be wary" or "to fear," in which case it is transitive through min (from), and "his precaution" (tuqātahu) or "precaution" (tuqiyyah) is in the accusative as a verbal noun (maṣdar), similar to His saying: "Fear Allah as He ought to be feared" (Āl ʿImrān: 102).