وَإِذا ضَرَبتُم فِي الأَرضِ فَلَيسَ عَلَيكُم جُناحٌ أَن تَقصُروا مِنَ الصَّلاةِ إِن خِفتُم أَن يَفتِنَكُمُ الَّذينَ كَفَروا ۚ إِنَّ الكافِرينَ كانوا لَكُم عَدُوًّا مُبينًا

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