Musannaf Ibn Abi Shaybah

Hazrat Haysam Muradi narrates that a man asked Hazrat Ibn Umar (may Allah be pleased with them both) about sleeping before the Isha prayer. He replied that one should sleep after offering the prayer. The man asked the same question three times, and he gave the same answer all three times. The third time, he said to him that one should sleep after offering the prayer; however, if you lie down, your eyes should not fall asleep.