[Remember] when He overwhelmed you with drowsiness [giving] security from Him and sent down upon you from the sky, rain by which to purify you and remove from you the evil [suggestions] of Satan and to make steadfast your hearts and plant firmly thereby your feet.
لِّيُطَهِّرَكُمso that He may purify youliyuṭahhirakum
بِهِۦwith itbihi
وَيُذۡهِبَand take awaywayudh'hiba
عَنكُمۡfrom youʿankum
رِجۡزَevil (suggestions)rij'za
ٱلشَّيۡطَٰنِ(of) the Shaitaanl-shayṭāni
وَلِيَرۡبِطَAnd to strengthenwaliyarbiṭa
عَلَىٰ[on]ʿalā
قُلُوبِكُمۡyour heartsqulūbikum
وَيُثَبِّتَand make firmwayuthabbita
بِهِwith itbihi
ٱلۡأَقۡدَامَyour feetl-aqdāma
Tafsir
And remember O believers when Allah made you fall asleep on that occasion, giving you a feeling of safety and peace from the fear you had of your enemy. He sent down rain from the sky on you, to purify you, and to remove the evil suggestions of Satan from you and to make your hearts strong, so you would be patient when you met the enemy in battle. It also made your feet firm, by making the sandy ground hard so that your feet would not sink and slip on it.