البقرة — Al-Baqarah Ayat 239
فَاِنْ خِفْتُمْ فَرِجَالًا اَوْ رُكْبَانًا ۚ فَاِذَآ اَمِنْتُمْ فَاذْكُرُوا اللّٰهَ كَمَا عَلَّمَكُمْ مَّا لَمْ تَكُوْنُوْا تَعْلَمُوْنَ
Fa'in khiftum farijālan au rukbānā(n), fa'iżā amintum fażkurullāha kamā ‘allamakum mā lam takūnū ta‘lamūn(a).
"And if you fear [an enemy, then pray] on foot or riding. But when you are secure, then remember Allah [in prayer], as He has taught you that which you did not [previously] know."