Abu Musa reported Allah's Messenger (ﷺ) as saying
A believer is like a brick for another believer, the one supporting the other.
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.
Nu'man b. Bashir reported a hadith like this from Allah's Apostle (ﷺ).
Nu'man b. Bashir reported Allah's Messenger (ﷺ) as saying
The believers are like one person; if his head aches, the whole body aches with fever and sleeplessness.
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.
A hadith like this has been narrated on the authority of Nu'man b. Bashir through another chain of transmitters.