Sunan an-Nasa'i, Volume 2, Book 15, Hadith 1435 (DarusSalam) ⓘ

It was narrated from Umayyah bin 'Abdullah bin Khalid that: He said to 'Abdullah bin 'Umar: "We find (mention of) prayer when one is at home (i.e., not traveling) and prayer at times of fear in the Qur'an, but we do not find any mention in the Qur'an of prayer when traveling. Ibn Umar said to him: 'O son of my brother, Allah (SWT) send Muhammad to us when we did not know anything, and all we should do is to do that which we saw Muhammad doing.'"

أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنِ ابْنِ شِهَابٍ، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي بَكْرِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ أُمَيَّةَ بْنِ عَبْدِ اللَّهِ بْنِ خَالِدٍ، أَنَّهُ قَالَ لِعَبْدِ اللَّهِ بْنِ عُمَرَ إِنَّا نَجِدُ صَلاَةَ الْحَضَرِ وَصَلاَةَ الْخَوْفِ فِي الْقُرْآنِ وَلاَ نَجِدُ صَلاَةَ السَّفَرِ فِي الْقُرْآنِ ‏.‏ فَقَالَ لَهُ ابْنُ عُمَرَ يَا ابْنَ أَخِي إِنَّ اللَّهَ عَزَّ وَجَلَّ بَعَثَ إِلَيْنَا مُحَمَّدًا صلى الله عليه وسلم وَلاَ نَعْلَمُ شَيْئًا وَإِنَّمَا نَفْعَلُ كَمَا رَأَيْنَا مُحَمَّدًا صلى الله عليه وسلم يَفْعَلُ ‏.‏