The Messenger of Allah ﷺ said, "The believer to another believer is like a building whose parts support one another."
حدثنا الحسن بن علي الخلال غير واحد قالوا حدثنا أبو أسامة عن بريد بن عبد الله بن أبي بردة عن جده أبي بردة
قال رسول الله ﷺ المؤمن للمؤمن كالبنيان يشد بعضه بعضا
Agreed upon [by Bukhari and Muslim]. Bukhari narrated it in the Book of Zakat, chapter on the reward of the servant who gives charity by his master's order without causing loss, hadith no. 1438, and Muslim, hadith no. 1023, from the hadith of Abu Usama, with this wording.