Musnad Ahmad 27:372

Rawh narrated to us, Shu'bah narrated to us, from Musa ibn 'Uqbah, I heard Salim ibn 'Abdullah say: Ibn 'Umar would almost curse the Bayda', and he would say: "The Messenger of Allah (peace and blessings of Allah be upon him) only entered into the state of Ihram from the mosque."