Silsilat al-Ahadith al-Sahihah

Ubaidullah bin Abdullah bin Utbah narrates from his father that Sabi’ah bint Harith’s husband passed away, and a few days later she gave birth to a child. After a few days, she was also purified from the blood of postpartum bleeding. Abu Sanabil passed by her and said: "You will not be lawful (for remarriage) until four months and ten days have passed." When she mentioned this to the Messenger of Allah (peace and blessings be upon him), he said: "Abu Sanabil is wrong; what he said is not the truth. In fact, you have become lawful (for remarriage) and you may marry. If a suitable man sends you a marriage proposal, come to me or inform me."