When is the time for Isha prayer, and when does it begin and end? Does it have a time of necessity, and what does that mean? And does the middle of the night differ from its last third?

The time for 'Isha prayer begins with the disappearance of the red twilight and its optional time extends until midnight, based on the Prophet's (peace be upon him) saying: "When you pray 'Isha, its time is until midnight." What is after midnight until the emergence of dawn is the time of necessity, and it is not permissible to delay the prayer until then except for those with excuses, such as sleep or forgetfulness. This opinion is supported by what Ibn Abbas narrated: "The time for 'Isha does not expire until Fajr." Midnight is calculated by dividing the time between sunset and dawn into two halves.