Take not as (your) Bitanah (advisors, helpers) (Surah Al-‘Imran 3: 118)

The Prohibition of Taking Advisors From Among the Disbelievers

Allah forbids His believing servants from taking the hypocrites as advisors, so that the hypocrites do not have the opportunity to expose the secrets of the believers and their plans against their enemies. The hypocrites try their very best to confuse, oppose and harm the believers any way they can, and by using any wicked, evil means at their disposal. They wish the very worst and difficult conditions for the believers. Allah said,

Take not as (your) Bitanah those other than your own in reference to taking followers of other religions as consultants and advisors, for advisors of a certain person have access to his most secret affairs. Al-Bukhari and An-Nasa'i recorded that, Abu Sa`id (Radhi Allahu Anhu) said that the Messenger of Allah (Sallallahu Alayhi wa Sallam) said,

Allah has not sent any Prophet nor was there any Khalifah but they have two types of advisors, one that commands him with righteousness and advises it, and another that commands him with evil and advises him with it. Only those whom Allah gives immunity are immune.

Ibn Abi Hatim reported that Ibn Abi Ad-Dahqanah said, "`Umar bin Al-Khattab (Radhi Allahu Anhu) was told, `There is young man here from the people of Hirah (in Iraq, who were Christians) who is a proficient scribe. Why do you not appoint him as a scribe' `Umar said, `I would then be taking advisors from among the disbelievers.''' This Ayah and the story about `Umar testify to the fact that Muslims are not allowed to use Ahl Adh-Dhimmah to be scribes in matters that affect the affairs of Muslims and expose their secrets, for they might convey these secrets to combatant disbelievers. This is why Allah said,

since they will not fail to do their best to corrupt you. They desire to harm you severely.

Allah then said,

Hatred has already appeared from their mouths, but what their breasts conceal is far worse.  meaning, enmity appears on their faces and in what they sometimes utter, as well as, the enmity they have against Islam and its people in their hearts. Since this fact is apparent to every person who has sound comprehension, therefore,

Indeed We have made plain to you the Ayat if you understand.

Source: Tafsir ibn Kathir (Abridged)