Musnad Ahmad 31:125

Hassan narrated to us, Ibn Lahi'ah narrated to us, Abu al-Zubayr narrated to us, from Jabir, from Abu Sa'id al-Khudri, that he said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "When one of you completes his prayer in the mosque, then returns to his house at that time, let him pray two rak'ahs in his house, and let him assign to his house a portion of his prayer, for Allah will place goodness in his house from his prayer."