Musannaf Ibn Abi Shaybah

Hazrat Qasim says that we used to visit Hazrat Aisha (may Allah be pleased with her) before the Fajr (probably should be Zuhr) prayer. One day we visited and she was praying. She said, "I was not able to perform my regular prayer during the night, so I did not consider it appropriate to leave it, therefore I am offering it at this time."