What was the proper time for Prophet Muhammad (peace be upon him) to pray according to the hadith shared by 'A'isha?
 'A'isha reported:                      The Apostle of Allah (may peace be upon him) one night delayed (observing the 'Isya' prayer) till a great part of the night was over and the people in the mosque had gone to sleep. He (the Holy Prophet) then came out and observed prayer and said: This is the proper time for it; were it not that I would impose a burden on my people (I would normally pray at this time). In the hadith transmitters by 'Abd al-Razzaq (the words are):" Were it not that it would impose burden on my people."