Shaykhul-Islaam Ibn al-Qayyim (may Allah have mercy upon him) stated:

Based upon this, when the Christians saw the Companions and that which they were upon, most of them believed by choice and willingly. They said, “Those who accompanied the Messiah are not better than these people.” We indeed called them and changed many of the People of the Book to come to Islaam (by Allah’s permission) and they informed us of that which prevented them (from accepting Islaam): it was what they had seen that those who attributed themselves to Islaam were upon, from those whom the ignorant magnified, from the affairs of bid’ah, oppression, corruption, scheming, and trickery.

Along with that is those matters being attributed to the legislation and those who came with it. As a result of that, they had an evil opinion of the legislation (of Islaam) and those who came with it. So Allah is the One will seek out those who cut off the path of Allah and He is their reckoner.

Source: Ighaathah al-Luhfaan 2/298

Translated by Abu Yusuf Khaleefah
14th of Jumaada al-Awwal, 1436 H (03-04-2015)
Masjid Nur Allah, Queens, NYC

Original Arabic

قال ابن القيم رحمه الله

ولهذا لمّا رأى النصارى الصحابة وما هم عليه آمن أكثرهم اختيارا وطوعا
وقالوا : ما الذين صحبوا المسيح بأفضل من هؤلاء ؟
ولقد دعونا نحن وغيرنا كثيرا من أهل الكتاب إلى الإسلام فأخبروا أن المانع لهم
ما يرون عليه المنتسبين إلى الإسلام ممّن يعظمهم الجُهّال : من البدع والظلم والفجور والمكر والاحتيال، ونسبة ذلك إلى الشرع ولمن جاء به فساء ظنهم بالشرع وبمن جاء به
فالله طليب قُطّاع طريق الله وحسيبهم