Hazrat Anas (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) forbade sleeping before the Isha prayer.

Hazrat Abu Barzah narrates that the Prophet (peace and blessings be upon him) used to forbid sleeping before the Isha prayer.

Ibrahim and Hazrat Mujahid state that Hazrat Ibn Umar (may Allah be pleased with them) used to condemn so strongly the one who slept before the Isha prayer that he was close to cursing him.

Hazrat Anas (may Allah be pleased with him) narrates that we used to stay away from our beds before the Isha prayer.

Hazrat Aslam narrates that Hazrat Umar wrote in a letter that no one should sleep before Isha, and if anyone lies down, his eyes should not fall prey to sleep.

The same is narrated through another chain.

Hazrat Saeed bin Yasar narrates that a man came to Hazrat Abu Hurairah and said, "We are warriors and soldiers; if we sleep before Isha, is there any harm in it?" He replied, "Yes, there is harm, there are two harms, rather there are three harms!"

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.

Hazrat Mujahid narrates that the Prophet (peace and blessings be upon him) said: If anyone lies down before Isha, he should not sleep.

Hazrat Ibn Abbas (may Allah be pleased with them) said: I do not like sleeping before ‘Isha and talking after ‘Isha at all.