Nu'man bin 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.
Hadith ReferenceSahih Muslim / The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship / Hadith: 2586