Abu Musa (May Allah bepleased with him) reported:
Messenger of Allah (ﷺ) said, "The relationship of the believer with another believer is like (the bricks of) a building, each strengthens the other." He (ﷺ) illustrated this by interlacing the fingers of both his hands.[Al-Bukhari and Muslim]. (DE)
Arabic/English book reference (DE): Book 1, Hadith 222 (DE)