Sunan Ibn Majah, Chapter: The Chapters on Divorce

It was narrated that Masruq and Amr bin Utbah wrote to Subaiah bint Harith, asking about her case: She wrote to them saying that she gave birth twenty-five days after her husband died. Then she prepared herself, seeking to remarry. Abu Sanabil bin Ba'kak passed by her and said: "You are in a hurry; observe waiting period for the longer period, four months and ten days." "So I went to the Prophet (saw) and said: 'O Messenger of Allah, (saw) pray for forgiveness for me.' He said: 'Why is that.” I told him (what had happened). He said: 'If you find a righteous husband then marry him."'