Sahih Bukhari Volume 1, Book 9, Hadith 571

قَالَ ابْنُ جُرَيْجٍ قُلْتُ لِعَطَاءٍ وَقَالَ سَمِعْتُ ابْنَ عَبَّاسٍ، يَقُولُ أَعْتَمَ رَسُولُ اللَّهِ صلى الله عليه وسلم لَيْلَةً بِالْعِشَاءِ حَتَّى رَقَدَ النَّاسُ وَاسْتَيْقَظُوا، وَرَقَدُوا وَاسْتَيْقَظُوا، فَقَامَ عُمَرُ بْنُ الْخَطَّابِ فَقَالَ الصَّلاَةَ‏.‏ قَالَ عَطَاءٌ قَالَ ابْنُ عَبَّاسٍ فَخَرَجَ نَبِيُّ اللَّهِ صلى الله عليه وسلم كَأَنِّي أَنْظُرُ إِلَيْهِ الآنَ، يَقْطُرُ رَأْسُهُ مَاءً، وَاضِعًا يَدَهُ عَلَى رَأْسِهِ فَقَالَ ‏"‏ لَوْلاَ أَنْ أَشُقَّ عَلَى أُمَّتِي لأَمَرْتُهُمْ أَنْ يُصَلُّوهَا هَكَذَا ‏"‏‏.‏ فَاسْتَثْبَتُّ عَطَاءً كَيْفَ وَضَعَ النَّبِيُّ صلى الله عليه وسلم عَلَى رَأْسِهِ يَدَهُ كَمَا أَنْبَأَهُ ابْنُ عَبَّاسٍ، فَبَدَّدَ لِي عَطَاءٌ بَيْنَ أَصَابِعِهِ شَيْئًا مِنْ تَبْدِيدٍ، ثُمَّ وَضَعَ أَطْرَافَ أَصَابِعِهِ عَلَى قَرْنِ الرَّأْسِ ثُمَّ ضَمَّهَا، يُمِرُّهَا كَذَلِكَ عَلَى الرَّأْسِ حَتَّى مَسَّتْ إِبْهَامُهُ طَرَفَ الأُذُنِ مِمَّا يَلِي الْوَجْهَ عَلَى الصُّدْغِ، وَنَاحِيَةِ اللِّحْيَةِ، لاَ يُقَصِّرُ وَلاَ يَبْطُشُ إِلاَّ كَذَلِكَ وَقَالَ ‏"‏ لَوْلاَ أَنْ أَشُقَّ عَلَى أُمَّتِي لأَمَرْتُهُمْ أَنْ يُصَلُّوا هَكَذَا ‏"

Ibn Juraij said, "I said to 'Ata', 'I heard Ibn 'Abbas saying: Once Allah's Apostle delayed the 'Isha prayer to such an extent that the people slept and got up and slept again and got up again. Then 'Umar bin Al-Khattab I, stood up and reminded the Prophet I of the prayer.' 'Ata' said, 'Ibn 'Abbas said: The Prophet came out as if I was looking at him at this time, and water was trickling from his head and he was putting his hand on his head and then said, 'Hadn't I thought it hard for my followers, I would have ordered them to pray ('Isha prayer) at this time.' I asked 'Ata' for further information, how the Prophet had kept his hand on his head as he was told by Ibn 'Abbas. 'Ata' separated his fingers slightly and put their tips on the side of the head, brought the fingers downwards approximating them till the thumb touched the lobe of the ear at the side of the temple and the beard on the face. He neither slowed nor hurried in this action but he acted like that. The Prophet said: "Hadn't I thought it hard for my followers I would have ordered them to pray at this time."