Musannaf Ibn Abi Shaybah

Hazrat Ja'far narrates from his father that Hazrat Ali (may Allah be pleased with him) bin Husain used to instruct the children to combine the Zuhr and Asr prayers, and to combine the Maghrib and Isha prayers. Someone said to him that in this way, they would be praying without regard to the proper time. Hazrat Ali (may Allah be pleased with him) bin Husain replied that this is better than them going to sleep without having prayed.