Do not take friends from the Jews and the Christians (Surah Al-Ma’idah 5: 51)

The Prohibition of Taking the Jews, Christians and Enemies of Islam as Friends

Allah forbids His believing servants from having Jews and Christians as friends, because they are the enemies of Islam and its people, may Allah curse them. Allah then states that they are friends of each other and He gives a warning threat to those who do this,

And if any among you befriends them, then surely he is one of them. Ibn Abi Hatim recorded that `Umar (Radhi Allahu Anhu) ordered Abu Musa Al-Ash’ari (Radhi Allahu Anhu) to send him on one sheet of balance the count of what he took in and what he spent. Abu Musa (Radhi Allahu Anhu) then had a Christian scribe, and he was able to comply with `Umar's demand. `Umar liked what he saw and exclaimed, "This scribe is proficient. Would you read in the Masjid a letter that came to us from Ash-Sham'' Abu Musa said, `He cannot.'' `Umar said, "Is he not pure'' Abu Musa said, "No, but he is Christian.'' Abu Musa said, "So `Umar admonished me and poked my thigh (with his finger), saying, `Drive him out (from Al-Madinah).' He then recited,

O you who believe! Take not the Jews and the Christians as friends... '' Then he reported that `Abdullah bin `Utbah said, "Let one of you beware that he might be a Jew or a Christian, while unaware.'' The narrator of this statement said, "We thought that he was referring to the Ayah,

O you who believe! Take not the Jews and the Christians as friends

Source: Tafsir ibn Kathir (Abridged)