Surah An-Nisa, ayah 101

وَإِذَا ضَرَبۡتُمۡ فِي ٱلۡأَرۡضِ فَلَيۡسَ عَلَيۡكُمۡ جُنَاحٌ أَن تَقۡصُرُواْ مِنَ ٱلصَّلَوٰةِ إِنۡ خِفۡتُمۡ أَن يَفۡتِنَكُمُ ٱلَّذِينَ كَفَرُوٓاْۚ إِنَّ ٱلۡكَٰفِرِينَ كَانُواْ لَكُمۡ عَدُوّٗا مُّبِينٗا ١٠١

Wa idhā darabtum fil-ardi falaysa 'alaykum junāhun an taqsurū minas-salawāti in khiftum an yaftinakumul-ladhīna kafarū innal-kāfirīna kānū lakum 'aduwwam mubīnā

And when you travel throughout the land, there is no blame upon you for shortening the prayer,²¹⁵ [especially] if you fear that those who disbelieve may disrupt [or attack] you.²¹⁶ Indeed, the disbelievers are ever to you a clear enemy.