Hadith 10:1088
Abu Bakr narrated to us, he said: Asbat bin Muhammad narrated to us, from Abd al-Malik, he said: Ata was asked about a woman whose husband dies while she is a Christian, then she accepts Islam; how long does she observe the waiting period? He said: Four months and ten [days].
حدثنا أبو بكر قال نا أسباط بن محمد عن عبد الملك قال سئل عطاء عن المراة يموت زوجها وهي نصرانية ثم تسلم كم تعتد قال أربعة أشهر وعشرا