Musnad Ahmad 26:549

I read to Yahya ibn Sa'id, from Hisham, Qatadah narrated to us, from Khallas, from 'Abdullah ibn 'Utbah, who said: 'Abdullah ibn Mas'ud was approached and asked about a man who married a woman and did not specify a dowry for her, then died before consummating the marriage with her. He did not say anything regarding it, so they returned, then they came to him and asked him. He said: "I will speak regarding it with the best of my opinion; if I am correct, then Allah, the Almighty and Majestic, has granted me success in that, and if I am wrong, then it is from me: She shall have the dowry of [like] her women, she shall have the inheritance, and she must observe the waiting period ('iddah)." A man from Ashja' stood up and said: "I bear witness regarding the Prophet, peace and blessings of Allah be upon him, that he judged with that." He said: "Bring someone who will testify to that for you." Then Abu al-Jarrah testified to that.