﴿ ثُمَّ يُجْزَىٰهُ ٱلْجَزَآءَ ٱلْأَوْفَىٰ ﴾

“where­upon he shall be requited for it with the fullest requital;”

then he will be rewarded for it with the fullest reward the most perfect reward one may say jazaytuhu sa‘yahu or jazaytuhu bi-sa‘yihi to mean the same thing