Shaykhul-Islam Ibn Taymiyyah (may Allah have mercy upon him) stated:

The corruption of the Jews and the Christians is apparent to the general Muslim masses. As for the people of innovation, then indeed their corruption is not apparent to every person (i.e. Muslim).

Source: Majmoo’ al-Fataawaa, 28/232

Translated by Abu Yusuf Khaleefah
28th Jumaadah Al-Awwal 1436 (19th March 2015)
Masjid Nur Allah, Queens, NY

Original Arabic

📜لمــاذا تركتــم اليهــود والنصــارى ؟ وتغتابــون دعــاة المسلميــن

:💎ﻗــﺎﻝ ﺷﻴــﺦ ﺍﻹﺳـﻼﻡ ﺍﺑـﻦ ﺗﻴﻤﻴـﺔ

((ﻓﺴﺎﺩ ﺍﻟﻴﻬﻮﺩ ﻭﺍﻟﻨﺼﺎﺭﻯ ﻇﺎﻫﺮ ﻟﻌﺎﻣﺔ ﺍﻟﻤﺴﻠﻤﻴﻦ ، ﺃﻣﺎ ﺃﻫﻞ ﺍﻟﺒﺪﻉ ﻓﺈﻧﻪ ﻻﻳﻈﻬﺮ ﻓﺴﺎﺩﻫﻢ ﻟﻜﻞ ﺷﺨﺺ )).

➖➖➖➖➖➖➖➖➖
:📎المصدر
ﻣﺠﻤﻮﻉ ﺍﻟﻔﺘﺎﻭﻯ ٢٨/ ٢٣٢.