Abu Hurayrah (radiyallahu ‘anhu) narrated that the Messenger of Allah ﷺ said:

المؤمن غِرٌّ كريم والفاجر خِبٌّ لئيم

“The believer is kind-hearted and noble, and the wicked is sly and malicious.” (Abu Dawud & al-Tirmidhi)

Imam al-Khattabi (rahimahullah) commented on this hadith:

The meaning of this statement is that the praiseworthy believer is one whose nature and disposition incline towards simplicity, lack of discernment for evil, and refraining from actively seeking it. This is not due to ignorance but rather reflects nobility and good character. Whereas the wicked person is one whose habit is deceitfulness, cunningness, and eagerness in knowing evil. This behavior does not stem from lack of intelligence but rather from deceitfulness and malice.

Source: Ma‘alim al-Sunan, explanation of Sunan Abi Dawud (4/108)

Shaykh al-Albani (rahimahullah) said:

Some might misunderstand the word “غر” (kind-hearted) to mean that the believer is naive or gullible, unable to handle worldly and religious matters properly. This misinterpretation has led some contemporary scholars to reject this hadith (and rule it as weak). However, the correct meaning of “غر” in this context refers to the believer’s natural disposition, which contrasts with that of the deceitful and malicious person. A malicious person is sly and deceptive in their interactions with others, often using un-Islamic means. In contrast, the believer is “غر”, we can say that he is pure-hearted and good-natured, unable to deceive others even though others might deceive him. This characteristic applies to worldly matters, while in matters of religion, the believer is among the most aware, alert, and intelligent. Therefore, “غر” refers to the believer’s worldly affairs and interactions with others, where he deals with people with good intentions and a clean heart.

The second part of the hadith explains that most people, if given the chance to take advantage of someone’s wealth or possessions by any means, would not hesitate. This behavior is not the characteristic of a true Muslim but rather of a deceitful and malicious person. Thus, the believer is kind-hearted and noble, while the wicked is sly and malicious.

Source: Audio Explanation of al-Adab al-Mufrad (Hadith 418).