Sahih al-Bukhari 4532

Narrated Muhammad bin Seereen:I sat in a gathering in which the chiefs of the Ansar were present, and `Abdur-Rahman bin Abu Laila was amongst them. I mentioned the narration of `Abdullah bin `Utba regarding the question of Subai'a bint Al-Harith. `Abdur-Rahman said, "But `Abdullah's uncle used not to say so." I said, "I am too brave if I tell a lie concerning a person who is now in Al-Kufa," and I raised my voice. Then I went out and met Malik bin 'Amir or Malik bin `Auf, and said, "What was the verdict of Ibn Mas`ud about the pregnant widow whose husband had died?" He replied, "Ibn Mas`ud said, 'Why do you impose on her the hard order and don't let her make use of the leave? The shorter Sura of women (i.e. Surat-at- Talaq) was revealed after the longer Sura (i.e. Surat-al-Baqara)." (i.e. Her 'Idda is until she delivers)