Musnad Ahmad 28:476

Rawh narrated to us, Thawr ibn Yazid narrated to us, from Uthman al-Shami, that he heard Abu al-Ash'ath al-San'ani, from Aws ibn Aws al-Thaqafi, from Abdullah ibn Amr ibn al-Aas, from the Prophet (peace and blessings of Allah be upon him), who said: "Whoever performs ghusl and causes ghusl to be performed, and goes early and sets out early, and draws near and approaches, and listens and remains silent, there shall be for him, for every step he takes, the reward of standing in prayer for a year and fasting it."