Nu'man b. Bashir reported that Muslims are like one body of a person; if the eye is sore, the whole body aches, and if the head aches, the whole body aches. (Using translation from Muslim 2586d)
قَالَ رَسُولُ اللهِ ﷺ الْمُؤْمِنُونَ كَرَجُلٍ وَاحِدٍ إِذَا اشْتَكَى رَأْسُهُ اشْتَكَى كُلُّهُ وَإِنْ اشْتَكَى عَيْنُهُ اشْتَكَى كُلُّهُ