Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) entered the mosque and saw a rope hanging between two pillars. The Prophet (peace be upon him) asked: Whose is this? The people replied: This belongs to Sayyidah Zainab (may Allah be pleased with her). She performs prayer, and when she becomes tired, she holds onto it. The Prophet (peace be upon him) said: Untie it. Then he said: A person should pray when he is active and energetic; if he feels tired or his heart is not inclined, then he should sit down.