Sahih Bukhari Volume 1, Book 9, Hadith 570

حَدَّثَنَا مَحْمُودٌ، قَالَ أَخْبَرَنَا عَبْدُ الرَّزَّاقِ، قَالَ أَخْبَرَنِي ابْنُ جُرَيْجٍ، قَالَ أَخْبَرَنِي نَافِعٌ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم شُغِلَ عَنْهَا لَيْلَةً، فَأَخَّرَهَا حَتَّى رَقَدْنَا فِي الْمَسْجِدِ، ثُمَّ اسْتَيْقَظْنَا ثُمَّ رَقَدْنَا ثُمَّ اسْتَيْقَظْنَا، ثُمَّ خَرَجَ عَلَيْنَا النَّبِيُّ صلى الله عليه وسلم ثُمَّ قَالَ ‏"‏ لَيْسَ أَحَدٌ مِنْ أَهْلِ الأَرْضِ يَنْتَظِرُ الصَّلاَةَ غَيْرُكُمْ ‏"‏‏.‏ وَكَانَ ابْنُ عُمَرَ لاَ يُبَالِي أَقَدَّمَهَا أَمْ أَخَّرَهَا إِذَا كَانَ لاَ يَخْشَى أَنْ يَغْلِبَهُ النَّوْمُ عَنْ وَقْتِهَا، وَكَانَ يَرْقُدُ قَبْلَهَا

Narrated By Ibn Juraij from Nafi : 'Abdullah bin 'Umar said, "Once Allah's Apostle was busy (at the time of the 'Isha), so the prayer was delayed so much so that we slept and woke up and slept and woke up again. The Prophet came out and said, 'None amongst the dwellers of the earth but you have been waiting for the prayer." Ibn 'Umar did not find any harm in praying it earlier or in delaying it unless he was afraid that sleep might overwhelm him and he might miss the prayer, and sometimes he used to sleep before the 'Isha prayer.