Silsilat al-Ahadith al-Sahihah

Sayyiduna Utbah bin Abd (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "If a man were to drag himself on his face in obedience to Allah from the day of his birth until the day he dies at extreme old age, he would still consider this (difficult and strenuous) deed insignificant on the Day of Resurrection."