كتاب الْمَسَاجِدِ وَمَوَاضِعِ الصَّلاَةِ
5  
The Book of Mosques and Places of Prayer
(39)
Chapter: The time of `Isha and delaying it
(39)
باب وَقْتِ الْعِشَاءِ وَتَأْخِيرِهَا ‏
Sahih Muslim 640 a

Thabit reported:

They (the believers) asked Anas about the ring of the Messenger of Allah (ﷺ) and he said: One night the Messenger of Allah (ﷺ) delayed (observing) the 'Isya' prayer up to the midnight or midnight was about to be over. He then came and said: (Other) people have offered prayers and slept, but you are constantly in prayer as long as you wait for prayer. Anas said: I perceive as if I am seeing the lustre of his silver ring, and lifted his, small left finger (in order to show how the Prophet had lifted it).
وَحَدَّثَنِي أَبُو بَكْرِ بْنُ نَافِعٍ الْعَبْدِيُّ، حَدَّثَنَا بَهْزُ بْنُ أَسَدٍ الْعَمِّيُّ، حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ ثَابِتٍ، ‏.‏ أَنَّهُمْ سَأَلُوا أَنَسًا عَنْ خَاتَمِ، رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ أَخَّرَ رَسُولُ اللَّهِ صلى الله عليه وسلم الْعِشَاءَ ذَاتَ لَيْلَةٍ إِلَى شَطْرِ اللَّيْلِ أَوْ كَادَ يَذْهَبُ شَطْرُ اللَّيْلِ ثُمَّ جَاءَ فَقَالَ ‏ "‏ إِنَّ النَّاسَ قَدْ صَلَّوْا وَنَامُوا وَإِنَّكُمْ لَمْ تَزَالُوا فِي صَلاَةٍ مَا انْتَظَرْتُمُ الصَّلاَةَ ‏"‏ ‏.‏ قَالَ أَنَسٌ كَأَنِّي أَنْظُرُ إِلَى وَبِيصِ خَاتَمِهِ مِنْ فِضَّةٍ وَرَفَعَ إِصْبَعَهُ الْيُسْرَى بِالْخِنْصَرِ ‏.‏
Reference : Sahih Muslim 640a
In-book reference : Book 5, Hadith 281
USC-MSA web (English) reference : Book 4, Hadith 1336
  (deprecated numbering scheme)