Musnad Ahmad 27:847

'Abd al-Rahman narrated to us, Malik narrated to us, from Nafi', from Ibn 'Umar, "That the Messenger of Allah (peace and blessings of Allah be upon him) used to pray two rak'ahs before Dhuhr and two rak'ahs after it, and two rak'ahs after Maghrib in his house, and two rak'ahs after 'Isha, and two rak'ahs after Jumu'ah in his house."