﴿ لِتَسْتَوُۥا۟ عَلَىٰ ظُهُورِهِۦ ثُمَّ تَذْكُرُوا۟ نِعْمَةَ رَبِّكُمْ إِذَا ٱسْتَوَيْتُمْ عَلَيْهِ وَتَقُولُوا۟ سُبْحَٰنَ ٱلَّذِى سَخَّرَ لَنَا هَٰذَا وَمَا كُنَّا لَهُۥ مُقْرِنِينَ ﴾

“in order that you might gain mastery over them, and that, whenever you have mastered them, you might remember your Sustainer’s blessings and say: “Limitless in His glory is He who has made [all] this subservient to our use - since [but for Him,] we would not have been able to attain to it.”

that you may sit that you may find a firm position upon their backs He has made the suffixed pronoun a masculine plural and rendered zahr ‘back’ plural because of the particle mā and its plural import; and then remember your Lord’s grace when you are settled on them and say ‘Glory be to Him Who has disposed this for us and we by ourselves were no match for it not capable of it.