question #3 Sahih al-Bukhari 945, Book 12, Hadith 4 : What can be learned about the flexibility of prayer times in Islam from this incident?

On the day of the Khandaq `Umar came, cursing the disbelievers of Quraish and said, “O Allah’s
Apostle! I have not offered the `Asr prayer and the sun has set.” The Prophet (ﷺ) replied, “By Allah! I too,
have not offered the prayer yet. “The Prophet (ﷺ) then went to Buthan, performed ablution and performed
the `Asr prayer after the sun had set and then offered the Maghrib prayer after it.”