Musannaf Ibn Abi Shayba 10:1148

Abu Bakr narrated to us, he said: Abu Khalid al-Ahmar narrated to us, from Muhammad ibn ‘Ajlan, from ‘Awf ibn Abi Jamila, who said: A friend of mine died and left a wife of his in Quba’. His wife came and said: "Ask Ibn ‘Umar: May I go out [at night] and stand over him [at his grave]?" So I came to Ibn ‘Umar, and he said: "You may go out during the day, but do not spend the night."