This question is in reference to the timings of ‘Isha Prayer. There are various opinions regarding when the time for offering ‘Isha prayer expires. Some say that one can pray ‘Isha till the Fajr Adhan is called, while others say that it expires at the time of "Tahajjud prayers". And finally some believe that we are supposed to take the number of hours between ‘Isha Adhan and the Fajr Adhan, and divide them into half, in order to estimate the last time for Isha prayer.
I know that prayers should be offered promptly and on time. Delaying a prayer without reason is not encouraged, but still it would be very beneficial to know the exact opinion on this issue.