Hadithcore
Riyad as-Salihin, 234

Abu Hurairah (May Allah bepleased with him) reported:

Messenger of Allah (ﷺ) said, "A Muslim is a brother to a Muslim. He should neither deceive him nor lie to him, nor leave him without assistance. Everything belonging to a Muslim is inviolable for a Muslim; his honour, his blood and property. Piety is here (and he pointed out to his chest thrice). It is enough for a Muslim to commit evil by despising his Muslim brother." <b>[At- Tirmidhi, who categorized it as Hadith Hasan]</b>.

وعن أبي هريرة رضي الله عنه قال‏:‏ قال رسول الله صلى الله عليه وسلم‏:‏ “المسلم أخو المسلم لا يخونه ولا يكذبه ولا يخذله، كل المسلم على المسلم حرام عرضه وماله ودمه، التقوى ههنا، بحسب امرئ من الشر أن يحقر أخاه المسلم” ‏(‏‏(‏رواه الترمذي وقال ‏:‏حديث حسن‏)‏‏)‏‏.‏

References1 variant
In-Book Reference
Introduction, Hadith 234
Sharh · explanationclick to expand
<b>Guidance from the Hadith:</b><br> 1) Despising Muslims is a sign of arrogance, which is all evil.<br> 2) A Muslim’s blood, honor, and property are inviolable, unless there is a Shariah-approved cause that cancels such inviolability.<br> 3) Piety withholds one from committing injustice, arrogance, and denial of the truth. It is only when piety grew weak that grievances have occurred between people.<br> Note:<br> Some people misunderstand this Hadith, so when you enjoin him to do good or forbid him from doing evil, he says, “Piety is here!” or that what counts is intention. The correct meaning though is that the heart is the cornerstone of piety; when the heart is pious, the body acts accordingly. Likewise, when the heart indulges in sin, the body acts accordingly. Thus, the state of the heart is reflected on the body parts.