A comparison for feeling other people's pain
The image is a body with a fever.
مَثَلُ الْمُؤْمِنِينَ فِي تَوَادِّهِمْ وَتَرَاحُمِهِمْ وَتَعَاطُفِهِمْ مَثَلُ الْجَسَدِ إِذَا اشْتَكَى مِنْهُ عُضْوٌ تَدَاعَى لَهُ سَائِرُ الْجَسَدِ بِالسَّهَرِ وَالْحُمَّى
The believers in their mutual love, mercy and compassion are like one body: when one limb complains, the rest of the body responds with sleeplessness and fever.
The full narration
Nu'man b. Bashir reported Allah's Messenger (ﷺ) as saying:The similitude of believers in regard to mutual love, affection, fellow-feeling is that of one body; when any limb of it aches, the whole body aches, because of sleeplessness and fever
Source
Ṣaḥīḥ Muslim · 6586
Ṣaḥīḥ
- Agreed upon as authentic (al-Bukhārī / Muslim)