Musnad Ahmad 1153:386

Aswad narrated to us, Sharik narrated to us, from Hisham, from his father, from Aisha, who said: "When Sawda grew old, she gifted her day to me, and the Prophet, may Allah bless him and grant him peace, would allot her day to me along with his [other] wives." She said: "And she was the first woman he married after me."