The Messenger of Allah ﷺ said, "A believer to another believer is like a building, each part strengthening the others," and he interlaced his fingers.
قال رسول الله ﷺ: المؤمن للمؤمن كالبنيان يشد بعضه بعضا وشبك بين أصابعه.
Bukhari narrated it in "Wrongs" (2446) and Muslim narrated it in "Righteousness, Kinship, and Manners" (2585), both from Muhammad bin Ala, who said, Abu Usama narrated to us, from Buraid, from Abu Burda, from Abu Musa Ashari, who said, and then he mentioned it.