Tirmidhi

(1) This hadith encourages the idea that a Muslim should always strive not to cause any kind of harm or distress to another Muslim; rather, he should prove to be beneficial to other Muslims, not harmful or injurious.

(2) Imam Hasan al-Basri rahimahullah was asked about the definition of “Abrar” (the righteous and pious person), so he replied: “They are those who do not harm even an ant and do not approve of even the slightest evil or wrongdoing.”

(3) This blessed hadith also refutes the misguided sect of the Murji’ah, whose belief is that after reciting the kalimah (testimony of faith), everyone’s Islam is complete and perfect, and no one’s Islam is deficient.

(4) The purpose of “muhajir” (emigrant) and migration (hijrah) is the protection of religion. If someone leaves his home and belongings but does not abandon disobedience to Allah Ta’ala, then his migration is purposeless. However, the one who abandons disobedience to Allah Ta’ala, even if he remains in his own home, has fulfilled the purpose of migration. And the real emigrant is he, not merely the one who leaves his home.

Hadith Authentication: It is authentic (sahih).
It has been narrated by Ibn Hibban [الاحسان : 180], Al-Hakim [المستدرك 10/1 ح 22], Ahmad ibn Hanbal [المسند 379/2 ح 8931], and Muhammad ibn Nasr al-Marwazi [تعظيم قدر الصلاة 599/3، 600 ح 637] through the chain of «ليث بن سعد عن محمد بن عجلان عن القعقاع بن حكيم عن أبى صالح ذكوان عن أبى هريرة رضي الله عنه».
◈ Al-Tirmidhi said:
«هذا حديث حسن صحيح»
◈ Ibn Hibban declared it authentic,
◈ Al-Hakim said it is authentic according to the conditions of Muslim.
◈ One of the narrators of this narration, Muhammad ibn ‘Ajlan, is a mudallis (one who practices tadlis). See: [طبقات المدلسين لابن حجر 98؍3، المرتبة الثالثة] and [جامع التحصيل للعلائي ص109] and [المدلسين لابي زرعة ابن العراقي 56] and [المدلسين للسيوطي 50] and [المدلسين للحلبي ص52] and [قصيدة الذهبي وقصيدة ابي محمود المقدسي والثقات لابن حبان 7؍386، 387] and [التدليس فى الحديث للدميني 145؍3]
⟐ This narration is with “‘an” (the ‘an‘ana form), therefore this chain is weak.

Now, a brief mention of some supporting narrations (shawahid) of this narration is presented:
➊ «المسلم من سلم المسلمون من لسانه ويده» [صحيح البخاري : 10 ومسلم : 64؍40، وأضواء المصابيح : 6]
➋ «المؤمن من أمنه الناس على دمائهم و أموالهم» [ابن ماجه : 3934 بلفظ «المؤمن من أمنه الناس على أموالهم وأنفسهم» وسنده صحيح وصححه ابن حبان، الموارد : 25، والحاكم1/10، 11 على شرطهما]
⟐ The meaning of «أنفسهم» and «دمائهم» is the same, therefore, with these supporting narrations, the narration of Muhammad ibn ‘Ajlan is authentic. «والحمد لله»