Hazrat Mak’hool says that the time for Isha is until one third of the night; during this period, there is no allowance for sleep or negligence.

Hazrat Ibn Umar (may Allah be pleased with them both) narrates that one night we were waiting for the Messenger of Allah (peace and blessings be upon him) for the ‘Isha prayer. When a third of the night or a little more had passed, the Messenger of Allah (peace and blessings be upon him) came. I do not know whether something had held him back or he had some need among his family. He said,“I do not know of any followers of a religion, besides you, who wait for this prayer. If I did not fear hardship for my Ummah, I would have ordered them to perform this prayer at this time.”

It is narrated from Hazrat Abu Hurairah that the Messenger of Allah, peace and blessings be upon him, said: If I did not fear hardship for my ummah, I would have delayed the Isha prayer until one third or half of the night had passed.

It is narrated from Hazrat Mu'adh bin Jabal, he says: One day we waited a long time for the arrival of the Prophet (peace and blessings be upon him) for the 'Isha prayer, but he delayed so much that a man said, "He will not come." Just then, the Prophet arrived, and a man said, "O Messenger of Allah! We thought that you had already performed the prayer and would not come now." The Noble Prophet (peace and blessings be upon him) said: "Offer this prayer in the darkness, for you have been given superiority over all other nations because of this prayer; the nations before you did not offer this prayer."

Hazrat Ibn Abbas (may Allah be pleased with both of them) narrates that the Messenger of Allah (peace and blessings be upon him) once delayed the ‘Isha prayer one night. When he arrived, drops of water were dripping from his blessed head. He said,“If I did not fear hardship for my Ummah, I would have fixed this time for this prayer.”

A man from Juhainah narrates that I asked the Messenger of Allah (peace and blessings be upon him): When should I perform the Isha prayer? He replied: When the night has reached into every valley, then perform it at that time.

Hazrat Abdur Rahman bin Ubaid narrates from his father that we used to offer the Maghrib prayer with Hazrat Nu'man bin Bashir; our last person would not have left the mosque yet when the time for Isha would arrive.

Hazrat Umar says: Offer the Isha prayer early, before the laborer becomes sluggish and the sick person falls asleep.