When you travel, during war, you commit no error by shortening your Contact Prayers (Salat), if you fear that the disbelievers may attack you. Surely, the disbelievers are your ardent enemies.
وَإِذا ضَرَبتُم فِى الأَرضِ فَلَيسَ عَلَيكُم جُناحٌ أَن تَقصُروا مِنَ الصَّلوٰةِ إِن خِفتُم أَن يَفتِنَكُمُ الَّذينَ كَفَروا إِنَّ الكٰفِرينَ كانوا لَكُم عَدُوًّا مُبينًا
wa izaa darabtum fil ardi falaisa ‘alaikum junaahun an taqsuroo minas Salaati in khiftum ai yaftinakumul lazeena kafarooo; innal kaafireena kaanoo lakum aduwwam mubeenaa