Riyad as-Salihin — Hadith #46226

On the authority of Al-Nu’man bin Bashir, may God be pleased with them both, he said: I heard the Messenger of God, may God’s prayers and peace be upon him, say: “You will straighten your rows, or God will dissent between your faces.” ((Agreed upon)) And in a narration by Muslim: The Messenger of God, may God’s prayers and peace be upon him, was straightening our rows as if he were straightening them with a sword, until he saw that we had turned away from him. Then he went out one day and stood up until He was about to grow up, and he saw a man with his chest visible from the row, and he said “Servants of God, may you straighten your rows, or God will discord between your faces.”