Sahih al-Bukhari 572
Sahih al-Bukhari · Book 9: Times of the Prayers · Time of the 'Isha prayer is up to the middle of the night
Narrated Anas:
حَدَّثَنَا عَبْدُ الرَّحِيمِ الْمُحَارِبِيُّ ، قَالَ حَدَّثَنَا زَائِدَةُ ، عَنْ حُمَيْدٍ الطَّوِيلِ ، عَنْ أَنَسٍ ، قَالَ أَخَّرَ النَّبِيُّ صلى الله عليه وسلم صَلاَةَ الْعِشَاءِ إِلَى نِصْفِ اللَّيْلِ، ثُمَّ صَلَّى ثُمَّ قَالَ " قَدْ صَلَّى النَّاسُ وَنَامُوا، أَمَا إِنَّكُمْ فِي صَلاَةٍ مَا انْتَظَرْتُمُوهَا " . وَزَادَ ابْنُ أَبِي مَرْيَمَ أَخْبَرَنَا يَحْيَى بْنُ أَيُّوبَ حَدَّثَنِي حُمَيْدٌ سَمِعَ أَنَسًا كَأَنِّي أَنْظُرُ إِلَى وَبِيصِ خَاتَمِهِ لَيْلَتَئِذٍ .
The Prophet (ﷺ) delayed the `Isha' prayer till midnight and then he offered the prayer and said, "The people prayed and slept but you have been in prayer as long as you have been waiting for it (the prayer)." Anas added: As if I am looking now at the glitter of the ring of the Prophet (ﷺ) on that night.