Musnad Ahmad 27:1306

Affan narrated to us, Hammad bin Salamah narrated to us, Humayd informed us, from Bakr bin Abdullah, from Ibn Umar, and Ayyub, from Nafi’, from Ibn Umar: "That the Prophet, peace and blessings of Allah be upon him, prayed Dhuhr, Asr, Maghrib, and Isha at al-Batha, then he slept there for a short sleep, then he entered Makkah." Ibn Umar used to do that.