Sunan an-Nasa'i, Volume 1, Book 6, Hadith 596 (DarusSalam)

Nafi' said: "I went out with 'Abdullah bin 'Umar on a journey to some of his land. Then someone came to him and said: 'Safiyyah bint Abi 'Ubaid is sick, try to get there before it is too late.' He set out quickly, accompanied by a man of the Quraish. The sun set but he did not pray, although I knew him to be very careful about praying on time. When he slowed down I said: 'The prayer, may Allah have mercy on you.' He turned to me but carried on until the twilight was almost gone, then he stopped and prayed Maghrib, then he said the Iqamah for 'Isha', at that time the twilight had totally disappeared and led us in prayer. Then he turned to us and said: 'If the Messenger of Allah was in a hurry to travel he would do this.'"

أَخْبَرَنَا مَحْمُودُ بْنُ خَالِدٍ، قَالَ حَدَّثَنَا الْوَلِيدُ، قَالَ حَدَّثَنَا ابْنُ جَابِرٍ، قَالَ حَدَّثَنِي نَافِعٌ، قَالَ خَرَجْتُ مَعَ عَبْدِ اللَّهِ بْنِ عُمَرَ فِي سَفَرٍ يُرِيدُ أَرْضًا لَهُ فَأَتَاهُ آتٍ فَقَالَ إِنَّ صَفِيَّةَ بِنْتَ أَبِي عُبَيْدٍ لَمَا بِهَا فَانْظُرْ أَنْ تُدْرِكَهَا ‏.‏ فَخَرَجَ مُسْرِعًا وَمَعَهُ رَجُلٌ مِنْ قُرَيْشٍ يُسَايِرُهُ وَغَابَتِ الشَّمْسُ فَلَمْ يُصَلِّ الصَّلاَةَ وَكَانَ عَهْدِي بِهِ وَهُوَ يُحَافِظُ عَلَى الصَّلاَةِ فَلَمَّا أَبْطَأَ قُلْتُ الصَّلاَةَ يَرْحَمُكَ اللَّهُ ‏.‏ فَالْتَفَتَ إِلَىَّ وَمَضَى حَتَّى إِذَا كَانَ فِي آخِرِ الشَّفَقِ نَزَلَ فَصَلَّى الْمَغْرِبَ ثُمَّ أَقَامَ الْعِشَاءَ وَقَدْ تَوَارَى الشَّفَقُ فَصَلَّى بِنَا ثُمَّ أَقْبَلَ عَلَيْنَا فَقَالَ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا عَجِلَ بِهِ السَّيْرُ صَنَعَ هَكَذَا ‏.‏

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also referenced under: Book 6, Hadith 602 (In-Book)