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.
The Saheeh International Quran Translation
فَإِنْ خِفْتُمْ فَرِجَالًا أَوْ رُكْبَانًا فَإِذَآ أَمِنتُمْ فَٱذْكُرُوا۟ ٱللَّهَ كَمَا عَلَّمَكُم مَّا لَمْ تَكُونُوا۟ تَعْلَمُونَAnd 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.