question #3 Sahih Muslim 638c, Book 5, Hadith 278 : What can be learned about the flexibility in prayer timings from the actions of the Prophet Muhammad (ﷺ)?

The Apostle of Allah (ﷺ) 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.”