Sahih al-Bukhari Book 9, Hadith 43
Allah's Messenger (ﷺ) once delayed the `Isha' prayer and that was during the days when Islam still had not
spread. The Prophet (ﷺ) did not come out till `Umar informed him that the women and children had slept.
Then he came out and said to the people of the mosque: "None amongst the dwellers of the earth has
been waiting for it (`Isha prayer) except you."
We asked Jabir bin `Abdullah about the prayers of the Prophet (ﷺ) . He said, "He used to pray Zuhr prayer at midday, the `Asr when the sun was still hot, and the Maghrib after sunset (at its stated time). The `Isha was offered early if the people gathered, and used to be delayed if their number was less; and the morning prayer was offered when it was still dark. "
My companions, who came with me in the boat and I landed at a place called Baqi . The Prophet (ﷺ) was in Medina at that time. One of us used to go to the Prophet (ﷺ) by turns every night at the time of the `Isha prayer. Once I along with my companions went to the Prophet (ﷺ) and he was busy in some of his affairs, so the `Isha' prayer was delayed to the middle of the night He then came out and led the people (in prayer). After finishing from the prayer, he addressed the people present there saying, "Be patient! Don't go away. Have the glad tiding. It is from the blessing of Allah upon you that none amongst mankind has prayed at this time save you." Or said, "None except you has prayed at this time." Abu Musa added, 'So we returned happily after what we heard from Allah's Messenger (ﷺ) ."