Sahih al-Bukhari 3991

Narrated Subaia bint Al-Harith: That she was married to Sa`d bin Khaula who was from the tribe of Bani 'Amr bin Luai, and was one of those who fought the Badr battle. He died while she was pregnant during Hajjat-ul-Wada.' Soon after his death, she gave birth to a child. When she completed the term of delivery (i.e. became clean), she prepared herself for suitors. Abu As-Sanabil bin Ba'kak, a man from the tribe of Bani Abd-ud-Dar called on her and said to her, "What! I see you dressed up for the people to ask you in marriage. Do you want to marry By Allah, you are not allowed to marry unless four months and ten days have elapsed (after your husband's death)." Subai'a in her narration said, "When he (i.e. Abu As-Sanabil) said this to me, I put on my dress in the evening and went to Allah's Messenger (ﷺ) and asked him about this problem. He gave the verdict that I was free to marry as I had already given birth to my child and ordered me to marry if I wished