Sahih al-Bukhari & Sahih Muslim

الْمُؤْمِنُ لِلْمُؤْمِنِ كَالْبُنْيَانِ يَشُدُّ بَعْضُهُ بَعْضًا

“The believer to another believer is like a building — each part strengthens the other.”

— Sahih al-Bukhari & Sahih Muslim, Bukhari 481, Muslim 2585