Sayyiduna Mughirah bin Shu’bah (may Allah be pleased with him) narrates that the Prophet Muhammad (peace and blessings be upon him) performed (so many voluntary) prayers that his blessed feet became swollen. It was said to him,“O Messenger of Allah, you are enduring this hardship and difficulty even though your past and future sins have been forgiven?”He (peace and blessings be upon him) replied:“Should I not be a grateful servant?”