Musnad Ahmad 27:853

Narrated to us Abd al-Rahman, from Malik, from Nafi, from Ibn Umar, that the Prophet, peace and blessings of Allah be upon him, used to, when it was a night of wind and cold while on a journey, command the caller to prayer (mu'adhdhin), so he would call the adhan. Then he would say: "Prayer is in the dwellings."